K Number
K041003
Date Cleared
2004-08-20

(123 days)

Product Code
Regulation Number
866.2660
Reference & Predicate Devices
N/A
Predicate For
AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP AuthorizedThirdpartyExpeditedreview
Intended Use

ImmunoCard® Toxins A & B is a rapid, qualitative, horizontal-flow enzyme immunoassay (ElA) for detecting Clostridium difficile toxins A and B in human stool. This assay is used as an aid in the diagnosis of C.difficile-associated disease.

Device Description

ImmunoCard Toxins A & B is distributed as a test kit that includes the following reagents: ImmunoCard Toxins A & B Test Device, Sample Diluent, Positive Control, Enzyme Conjugate, Wash Reagent, and Substrate Reagent. The test device is a chromatography strip membrane pad housed in a plastic frame. The membrane carries immobilized monoclonal anti-Toxin A and goat polyclonal anti-Toxin B at the TEST reaction port and crude C. difficile toxin at the CONTROL reaction port. The Enzyme Conjugate Reagent consists of antibodies to toxins A and B coupled to horseradish peroxidase. The test involves diluting a stool sample with Sample Diluent and Enzyme Conjugate, incubating, adding the mixture to sample ports on the test device, incubating again, washing, adding Substrate Reagent, incubating, and visually reading the result based on the appearance of a blue color in the reaction ports.

AI/ML Overview

Here's a summary of the acceptance criteria and study details for the ImmunoCard® Toxins A & B device, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria (e.g., "must achieve X% sensitivity"). Instead, it presents the device's performance characteristics and compares them to predicate devices and the standard ground truth method (cytotoxin assay). The implicit acceptance is that the device's performance metrics are comparable or superior to predicate devices and acceptable for diagnostic aid.

Performance MetricAcceptance Criteria (Implicit)Reported ImmunoCard® Toxins A & B Performance
Clinical SensitivityComparable to/better than predicate devices and standard method95.2% (Overall)
Clinical SpecificityComparable to/better than predicate devices and standard method98.5% (Overall)
Predictive Value of a Positive TestComparable to/better than predicate devices and standard method93.5% (Overall, incidence = 1%)
Predictive Value of a Negative TestComparable to/better than predicate devices and standard method99.0% (Overall)
Precision/Reproducibility100% within and between test sites100%
Analytical Sensitivity (Limit of Detection)Not explicitly stated for acceptance, but a target of 3 ng/mL is implied3 ng/mL for both Toxin A and Toxin B
Cross-reactivity (Microbial)No interference from common stool microbes (except related C. sordellii)Only Clostridium sordellii (VPI 9048) caused a false positive
Cross-reactivity (Non-Microbial/Drugs)No significant interference from common drugs/substances in stoolFecal fat, metronidazole, whole blood, vancomycin, mucin, barium sulfate, Imodium AD®, Kaopectate® Caplets, Pepto Bismol® were tested and did not show significant interference based on the defined criteria (+/- 3 grades from control average).
High Dose Hook EffectNoneNone observed

2. Sample Size Used for the Test Set and Data Provenance

  • Total Clinical Test Set Sample Size: 591 samples
  • Data Provenance: Archival human stool samples collected from symptomatic patients. The study was conducted across three independent clinical laboratories and Meridian Bioscience's Development Laboratory. The data is retrospective, as it uses "archival samples collected from symptomatic patients that had been ungrouped for toxins."

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

  • Number of Experts: Not explicitly stated as "experts." However, the "cytotoxin and neutralization" assay served as the gold standard for ground truth. This assay requires specialized laboratory personnel to perform and interpret. The text states: "Meridian's Development Laboratory was responsible for performing all confirmation cytotoxin assays for Site 1 and Site 3." This implies trained laboratory personnel are involved.
  • Qualifications of Experts: Not explicitly detailed beyond "Meridian's Development Laboratory." The cytotoxin assay is described as "the most accurate assay overall for the detection of C. difficile."

4. Adjudication Method for the Test Set

  • The ground truth was established by the cytotoxin and neutralization assay. This method itself is the gold standard, implying its results were taken as the definitive truth. The text states: "The status of all samples (whether positive or negative by ImmunoCard) was confirmed by cytotoxin and neutralization."
  • For samples producing discordant results between ImmunoCard and the cytotoxin assay, some were re-tested (e.g., 3-103, 3-118, 3-241 were "converted to positive on repeat testing at 1:10 dilution" in the cytotoxin assay). However, it's not described as a formal adjudication by an independent panel.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

  • No MRMC comparative effectiveness study was done to assess how much human readers improve with AI vs. without AI assistance. This device is a rapid diagnostic assay, not an AI-assisted diagnostic tool interpreted by human readers.

6. Standalone (Algorithm Only Without Human-in-the-Loop) Performance

  • This device is a standalone diagnostic kit (ImmunoCard® Toxins A & B), not an "algorithm." Its performance is evaluated directly in comparison to the gold standard (cytotoxin assay) and predicate devices. There is no human-in-the-loop component in the interpretation of the test device's result beyond visual assessment of color change. The test result (appearance of blue color in the test port) is directly interpreted.

7. Type of Ground Truth Used

  • Expert Concensus / Gold Standard Laboratory Method: The primary ground truth used for performance evaluation was the cytotoxin and neutralization assay. This is considered the "standard method" for detecting C. difficile toxins.

8. Sample Size for the Training Set

  • The document implies that the study was primarily for validation against a reference standard, not for training a machine learning algorithm. Therefore, there is no "training set" in the context of AI. The performance evaluation was done on a test set of 591 archival samples.

9. How the Ground Truth for the Training Set Was Established

  • Not applicable, as there is no mention of a training set for an AI algorithm. The assay is a lateral flow immunoassay where the "ground truth" for its development would be based on biochemical binding and detection principles calibrated against known concentrations of toxins and validated with clinical samples against the gold standard (cytotoxin assay).

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AUG 2 0 2004

510(k) SUMMARY OF SAFETY & EFFECTIVENESS

IDENTIFICATION INFORMATION

SUBMITTER'S INFORMATION

This summary of 510(k) safety and effectiveness is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

The assigned 510(k) number is:_K041003

SUBMITTER'S NAME AND ADDRESS: Meridian Bioscience, Inc. 3471 River Hills Drive Cincinnati, OH 45244

PHONE NUMBER: (513) 271-3700

FAX NUMBER: (513) 272-5213

CONTACT PERSON: Susan Rolih Vice President, Regulatory Affairs and Quality Assurance Official Correspondent

DATE SUMMARY PREPARED: August 18, 2004

NAME OF DEVICE: ImmunoCard® Toxins A & B (ImmunoCard is a registered trademarks of Meridian Bioscience, Inc.)

COMMON NAME: Reagent, C. difficile toxins

CLASSIFICATION NAME: Reagents, C. difficile toxin [83(LLH)]

REGULATION: 866.2660

PREDICATE EQUIVALENT DEVICES: Premier Toxins A & B (Meridian Bioscience, Inc.), ImmunoCard Toxin A (Meridian Bioscience, Inc.), C. difficile Tox A/B II (Techlab, Inc.), Oxoid Clearview C. difficile Toxin A (Unipath, Ltd.), ColorPAC Toxin A (Becton Dickinson)

INTENDED USE:

ImmunoCard® Toxins A & B is a rapid, qualitative, horizontal-flow enzyme immunoassay (ElA) for detecting Clostridium difficile toxins A and B in human stool. This assay is used as an aid in the diagnosis of C.difficile-associated disease.

BACKGROUND:

Toxigenic Clostridium difficile is the leading cause of nosocomial infectious diarrhea in developed countries. An estimated 300,000 cases of C. difficile associated disease (CDAD) are seen per year in U.S. hospitals alone. (1.2) Clostridium difficile is the etiologic agent in approximately 25% of all cases of antibiotic-associated diarrhea. Virtually any antibiotic can predispose a patient to CDAD. The clinical presentation for CDAD ranges from asymptomatic colonization to life-threatening pseudomembranous colitis and toxic megacolon. (2) Most pathogenic strains of C. difficile produce two biologically and immunologically distinct toxin A (enterotoxin) and toxin B (cytotoxin). Toxin A was once thought to be responsible for most of the pathology seen in human CDAD until reports of clinically relevant disease caused by strains of C. difficile that produce only toxin B began to appear in the late 1990's. (1)

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The most accurate assay overall for the detection of C. difficile is the cytotoxin assay, however the The most acourate used on the are and and is not standardized. (2) The use of memod requires lisode bakare labilition 10 && enables the physician to verify infection quickly, begin a rapid toot one and to initiate enteric isolation precautions in a hospital setting. (2)

INDICATIONS FOR USE

lmmunoCard® Toxins A & B is a rapid, qualitative, horizontal-flow enzyme immunoassay (ElA) for detecting Clostridium difficile toxins A and B in human stool. This assay is used as an aid in the diagnosis of C.difficile-associated disease.

Sypmtoms of the disease include:

  • Nosocomial infectious diarrhea 1.
  • Antibiotic-associated diarrhea 2.

Contraindications

There are no contraindications associated with the use of this product.

Special instrument requirements

No instruments are used with this product.

Combination with other medical devices

No other medical devices are used in combination with this device.

DEVICE DESCRIPTION AND TECHNOLOGICAL PRINCIPLES

Reagents

ImmunoCard Toxins A & B is distributed as a test kit that includes the following reagents:

ImmunoCard Toxins A & B Test Device: A chromatography strip membrane pad housed in a plastic frame and enclosed in a foil pouch with a desiccant. The membrane carries immobilized monoclonal anti-Toxin A and goat polyclonal anti-Toxin B at the TEST reaction port and crude C. difficile toxin at the CONTROL reaction port.

Sample Diluent: A buffered salt protein solution containing thimerosal (0.02%) as a preservative.

Positive Control: Inactivated crude C. difficile Toxin suspension in buffered solution containing thimerosal (0.02%) as a preservative.

Enzyme Conjugate: A blend of goat polyclonal antibodies to Toxins A and B conjugated to horseradish peroxidase and suspended in a buffered protein solution containing thimerosal (0.02%).

Wash Reagent: A buffered solution containing thimerosal (0.02%) as a preservative.

Substrate Reagent: A buffered solution containing tetramethyl-benzidine and peroxide.

Equipment needed to use the device

There is no equipment needed to use this device.

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Cross reactivity, Interfering substances and Analytical Specificity

There are no known interfering substances that affect the performance of this device.

Drugs. Nonmicrobial Substances

Drugs, Normicrobial Substances that might be present in stool (such as fecal fat, To show that drigs of other nonmoroblar outbeatlers than may results, tests were performed with five known positive and five known negative samples spiked with the potentially interfering material. Known positive and the Rhown Hoganve Spiked with the inert agent phosphate-buffered saline (PBS), Oonlines, consisting of the barno blood of each group of spiked samples were summed and averaged then were tested in paraliti. The grades or age. A substance was considered to interfere when it changed compared to the relovant serials by +/- three or more grades from the control average. As is the Tesult of the group avorage by Illowing substances had a significant effect on the test results:

Fecal fat, metronidazole, whole blood, vancomycin, mucin, barium sulfate, Imodium AD®, Kaopectate® Caplets, Pepto Bismol®.

Microbial organisms (potentially cross-reactive species)

Microbial engaments (percents A & B is specific for C. difficile toxins, known positive and negative stool specimens were first spiked with bacterial, viral and yeast strains, then tested using ImmunoCard. The bacteria, yeast and viruses selected were those that might be expected to be present in human stools either as part of normal flora or from a disease state. The final concentration of bacteria or yeast in each sample was > 1 x 108 organisms/ml. Unspiked stool was tested in parallel to provide a reference against which the reactions with spiked stools could be compared. Reactions (the rolerse of a blue color in the test port) were graded using a 10 point scale, where "0" equals no reaction and "10" equals the strongest color development and a positive reaction. In all test cases, the Control Port was expected to produce a positive reaction of ≥2. Organisms causing interference were those that diminished positive reactions by 2 or more grades, that caused a positive to become negative, or that caused the appearance of a positive reaction in a formerly negative sample.

As is shown in Table 2, only one of the microorganisms influenced test results. The organism, a related toxigenic form of Clostridium sordellii, caused a positive result in a negative stool.

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SampleIDPBS (control)StericAcid/PalmiticAcid (fecal fat)(4.8% w/v)Metronidazole(0.25% w/v)Whole blood(40% v/v)Vancomycin(0.25% w/v)Mucin(3.5% w/v)Bariumsulfate(5% w/v)Imodium ADLoperamideHCl(5% w/v)KaopectateAttapulgite(5 mg/mL))Pepto Bismol(5% w/v)
CTCTCTCTCTCT
P1343434/544343434
P233324433234333
P3323332423$1/2$4441
P434343534$1/2$434/534
P5323$1/2$3232424322
Total +grade15151514.51617.5171513.514.51818.51515.516
Average- grade3332.93.23.53.432.72.93.63.733.13.2
N130304040303040
N230404040304020
N330303040303040
N430302040303020
N5203030$1/2$0403030
Totalgrade14016016017.50160160150
Average- grade2.803.203.203.503.203.2030

able 1. Affect of drugs and nonmicrobial substances on positive and negative test result

Control results

DonControlest Port
mmunoCard Positive Control
" " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " "'mmunoCard Negative Contrc

Legend: LP = low positive (as defined by Premier Toxins A & B ElA), C = control port, T = test por, P = positive, + = positive, - = negative

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Table 2. Affect of microbial organisms on positive and negative test results.

Spiked intoPositive StoolSpiked intoNegative Stool
OrganismATCC # or ID #ControlPortTestPortControlPortTestPortOrganism effectsoutcome?
Unspiked stool controlNot applicable3-42-32-40Not applicable
Adenovirus 40 (1:125) (exp. 30Jul04)01080032H3240No
Adenovirus 41 (exp. 15Jan05)4017441.0084330No
Aeromonas hydrophila356543330No
Bacillus cereus117783230No
Bacillus subtilis60514340No
Bacteroides fragilis237454230No
Campylobacter coli499413330No
Campylobacter jejuni294283230No
Candida albicansBHI 150043340No
Clostridium butyricum48554230No
Clostridium difficile (non-toxogenic) Q11620-3/283220No
Clostridium difficile (non-toxogenic) Q12UNC199042230No
Clostridium difficile (non-toxogenic) Q13X-15076-590-1/203340No
Clostridium difficile (non-toxogenic) Q156113230No
Clostridium difficile (non-toxogenic) Q17234-250393230No
Clostridium difficile (non-toxogenic) Q182C62-1/314130No
Clostridium difficile (non-toxogenic) Q19111863230No
Clostridium difficile (non-toxogenic) Q202C1652130No
Clostridium difficile (non-toxogenic) Q32TCH33240No
Clostridium difficile (non-toxogenic) Q31C1242240No
Clostridium perfringens36243220No
Clostridium septicum1246431/230No
Clostridium sordelliiVPI 90483231Yes
Clostridium sordellii97144340No
Clostridium sporogenes358432/340No
Enterobacter cloacae32513240No

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Table 2 continued.

OrganismATCC # or ID #ControlPortTestPortControlPortTestPortOrganism effectsoutcome?
Escherichia coli 0157:H7438953330No
Eschericia coli 0157:H7EMDI-0123230No
Escherichia coli87394240No
Escherichia coli96373330No
Helicobacter pylori435043340No
Klebsiella pneumoniae138833230No
Peptostreptococcus anaerobius273373230No
Porphyromonas asaccharolytica252604330No
Proteus vulgaris63803230No
Pseudomonas aeruginosaMeridian Microbank # 182330No
Rotavirus (20Aug08)TRV0613240No
Salmonella typhimurium140283340No
Serratia liquefaciens355514330No
Shigella dysenteriaeMeridian Microbank # 143330No
Shigella flexneriMeridian Microbank # 153330No
Shigella sonneiMeridian Microbank # 63340No
Staphylococcus aureus65384340No
Staphylococcus aureus (Cowans I)125984440No
Staphylococcus epidermidis122283230No
Streptococcus faecalisMeridian Microbank # 74240No
Vibrio parahaemolyticus178023330No
Yersinia enterocoliticaMeridian Microbank # 104330No

Calibrators

There are no calibrators used with this device.

Controls

The assay includes an internal control (control port) that is used to demonstrate that sample has been applied, that it has flowed correctly and that the Enzyme Conjugate is active at the time of testing. In addition, a Positive Control Reagent and Sample Diluent (used for a negative control reagent) are supplied as external controls. Proper results obtained with the Control Port, Positive Control and negative control Diluent serve as indicators that the test was performed correctly, that the antibodies embedded in the membrane and the Enzyme Conjugate are active at the time of testing, and that the membrane supports proper sample flow. Failure of the internal and external control to produce the expected results suggests the test was not performed correctly (ie, incorrect volume of reagents added; incorrect incubation temperature or times used or that reagents were not brought to room temperature prior to testing).

Technological principles

ImmunoCard Toxins A & B consists of a membrane held in a plastic frame with two sample ports and two reaction ports. The membrane carries immobilized antibodies to toxins A and B. The Enzyme Conjugate Reagent consists of antibodies to toxins A and B coupled to horseradish peroxidase. To perform the test, patient stool sample is diluted with Specimen Diluent and Enzyme Conjugate and the

{6}------------------------------------------------

mixture is incubated for 5 minutes. During the incubation, molecules of toxin, if present, are bound to the anti-toxin antibodies of the Conjugate. Following incubation, an aliquot of the mixture is added to the anti-oally antiloodio of the Gorijagens: 's incubated for an additional 5 minutes at 20-26 C. During each of the two sample portune the tool is separated from particulate matter as the fluid the second nodbation the toxin serijagais romane to the TEST and CONTROL reaction ports. The portion of the bample frome in bug captured at the TEST reaction port by immobilized antitoxin in the reaction membrane. (The second of the two reaction ports serves as an internal control.) Both reaction ports are subsequently wash Reagent to reduce interference by contaminating roution porto and basedgement is added. The reaction ports are incubated for an additional 5 process during which time the enzyme conjugate modifies the Substrate Reagent. The result is the minutes dailing which the eneyms sen read visually. Development of a blue color in the TEST reaction port indicates a positive test. In the CONTROL port, the anti-toxin antibodies of the conjugate roution por in the immobilized toxin. The appearance of blue in the CONTROL reaction port indicates bird directly to the infribalized were active at the time of use and that proper sample migration occurred.

CharacteristicsIC Toxins A& BCytotoxin/Neutralization(Std)PremierToxinsA & BBDColorPACToxin AOxoidC. difficileToxinDetectionWampoleC. difficileTox A/B II
Device Type
In vitro diagnostic deviceYesYesYesYesYesYes
ControlNoNoNoNoNoNo
CalibratorNoNoNoNoNoNo
Intended Use
Detection of Toxins A and B in humanstoolYesYesYesOnly AOnly AYes
Detection of Toxins A and B in cultureNoYesYesOnly ANoYes
Screening testYesNoYesYesYesYes
Diagnostic testNoYesNoNoNoNo
Monitoring therapyNoYesNoNoNoNo
Acceptable Sample
Formed stoolYesYesYesYesYesYes
Semi-solid stoolYesYesYesYesYesYes
Liquid stoolYesYesYesYesYesYes
Stool collected in transport mediaNoNoNoNoNoNo
Broth cultureNoYesYesYesNoYes

SUBSTANTIAL EQUIVALENCE TO PREDICATE DEVICES

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Performance Characteristics(rounded) in Direct Comparisonto Clinical Status or ConditionIC ToxinsA & BCytotoxin(Std)PremierToxins A& BBDColorPACToxin AOxoid C.difficileToxinDetectionWampoleC. difficileTox A/B II
Clinical Sensitivity95.2%94.7%81%83.3%92.2%
Clinical Specificity98.5%97.3%97%96.7%100%
Predictive Value of a Positive Test(incidence = 1%)93.5%87.4%ND91.7%100%
Predictive Value of a Negative Test99%98.9%ND93.2%98.6%
Correlation98%96.9%NDND98.8%
Laboratory Equivalence inStool tests with (PredicateDevice)(cellcytotoxicity)(cytotoxin B)(cellcytotoxicityandneutralizationTissueculture
Concordance of positive tests withpredicate device95%90/95 (95%)96/119 (81%)110/132(83%)165/179(92%)
Discordance of positive tests withpredicate device5%5/95 (5%)23/119 (19%)22/132 (17%)14/179 (8%)
Concordance of negative tests withpredicate device98%465/478(97%)622/641(90%)301/311(97%)973/973(100%)
Discordance of negative tests withpredicate device2%13/478 (3%)19/641 (10%)10/311 (3%)0/973 (0%)
Performance characteristics
Precision/Reproducibility (intra-assay)100%See insert100%NDND
Precision/Reproducibility (inter-assay)100%See insert100%NDND
Linearity/reportable rangeNASee insertN/ANDND
Limit of detection3 ng/mL1.2 ng/mL A2.4 ng/mL BND>0.8 ng/mL A>2.5 ng/ML B
Liquid stoolND1.38-5.21NDND
Semi-solid stoolND1.61 - 18.71NDND
Solid stoolND3.19-22.58NDND
Assay cutoffNASee insertN/AN/ASee insert

:

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Me.

Comparison of Assay Methods

CharacteristicICTABPremier Toxins A & BBD ColorPACOxoid C. difficile Toxin AWampole Tox A/B II
Intended useDetection of toxins in human stoolDetection of toxins in human stool and broth cultureDetection of Toxin A in human stool or broth cultureDetection of Toxin A in human stoolDetection of Toxins A and B in fecal specimens and broth culture
Specimen Required1. Human stoolHuman stool1. Human Stool2. Broth cultureHuman stoolHuman stoolHuman stool in prep soln
TechnologyHorizontal-flow EIAMicroplate-based EIARapid chromatographic assayRapid chromatographic assayMicrowell based EIA
Level of skill requiredModerate complexityModerate complexityModerate complexityModerate complexityModerate complexity
Assay steps1. Add 200 uL Sample Diluent to a tube2. Add 3 drops Enzyme Conjugate.3. Add 25 uL stool to tube, vortex and let stand 5 min.4. Vortex sample mixture.5. Add 150 ul. diluted sample to test and control ports.6. Incubate 5 min., 20-26°C.7. Add 3 drops Wash Reagent to each port.8. Add Substrate.9. Incubate 5 min, 20-26 C.10. Read at end of incubation.1. Add 200 ul. Sample Diluent to a tube.2. Add 50 ul, stool and vortex.3. Add 100uL diluted sample to test well.4. Add 1 drop Enzyme Conjugate to well.5. Incubate 50 min, 35-39 C.6. Wash wells with Wash Buffer.7. Add 2 drops Substrate and shake plate and wait 30 seconds.8. At 2 drops Stop Solution.9. Wait 2 minutes then read at OD at 450 nm or 450/630nm.1. Add 1 mL Sample Buffer to tube.2. Add 0.5 mL or 0.5 g stool and vortex.3. Add 3 drops diluted sample to test device4. Add 1 drop Wash Reagent and absorb.5. Add 1 drop Detector A and wait 3 minutes.6. Add 1 drop Wash Reagent and absorb.7. Add 1 drop Detector B and wait 3 minutes.8. Add 1 drop Wash Reagent and absorb.9. Read after 1 minute.1. Add 1 mL Sample Diluent to tube.2. Add 100 uL or stool bead to tube and vortex.3. Centrifuge sample to separate solids from supernate.4. Add 125 ul supernate to Test Unit.5. Incubate 30 minutes.6. Read test at end of 30 minutes.1. Add 200 uL Diluent to tube.2. Add 50 uL of stool to tube and vortex.3. Add 1 drop Conjugate to test well.4. Add100 uL of diluted specimen.5. Incubate, 37 C, 50 minutes.6. Wash wells with Wash Solution7. Add 100 uL Substrate8. Incubate for 10 minutes.9. Add 1 drop Stop Solution and wait 2 minutes.10. Read at OD 450 nm.
End pointAppearance of blue colorAppearance of yellow colorAppearance of pink lineAppearance of blue lineAppearance of yellow color
Interpretation of test resultPositive = appearance of blue color in test and control ports (indicates presence of toxin)Negative = no color in test port with blue color in reaction port (indicates absence of toxin)Positive = appearance of yellow color in test and positive control wells (indicates presence of toxin)Negative = no color in test well with yellow color in positive control (indicates absence of toxin)Positive = appearance of a pink line at test and control points (indicates presence of toxin)Negative = no color at test point with pink color at control pointPositive = appearance of a blue line at test and control points (indicates presence of toxin)Negative = no color at test point with blue color at control pointPositive = appearance of yellow color in test and positive control wells (indicates presence of toxin)Negative = no color in test well with yellow color in positive control (indicates absence of toxin)

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CLINICAL TRIALS

Two independent laboratories and Meridian's Development Laboratory performed testing on archival I wo independent laboratione and incraraneles collected from symptomatic patients that had been (it croupolited for toxing. Each laboratory tested the samples by its own reference method (if applicable), a predicate device and ImmunoCard Toxins A and B. The status of all samples (whether applicable), a products and was confirmed by cytotoxin and neutralization. Because of their positive of negative by immunoodial was evelles and the responsibility of performing all confirmation cytotoxin assays for Site 1 and Site 3.

Investigators were required to record the age and sex of the patient, the consistency, appearance and involugation thou specimen at the time of testing. Samples were tested fresh (stored at 2-8 C for no more than 72 hours) or after frozen storage at < -20 C.

Patient characteristics (patient age, sex)

The age of the patients included in the clinical trial ranged from 1 to 99 years. Males and females were equally represented. Less than 2% of the 591 samples tested were from pediatric patients (≤15 years) therefore the IFU carries the limitation that the performance of specimens from pediatric patients has not been evaluated. It is expected however, there will be a higher incidence of positive tests in asymptomatic pediatric patients because of the carrier state associated with this population. There were no significant differences in test results attributable to age or sex in tests performed with samples from adult patients.

Patient Age and Sample Storage<1 Yr.1-5 Yrs6-15 Yrs> 15 YrsNot defined
Clinical site 1
Total tested Fresh002140N/A
Mean positive reaction strengthN/AN/AN/A6.6N/A
Positive reaction rangeN/AN/AN/A1-10N/A
Total tested Frozen01051N/A
Mean positive reaction strengthN/AN/AN/A5.7N/A
Positive reaction rangeN/AN/AN/A1-10N/A
Clinical site 2
Total tested Fresh0000N/A
Mean positive reaction strengthN/AN/AN/AN/AN/A
Positive reaction rangeN/AN/AN/AN/AN/A
Total tested Frozen03151N/A
Mean positive reaction strengthN/A8.0N/A8.0N/A
Positive reaction rangeN/A1-10N/A1-10N/A
Clinical site 3
Total tested FreshN/AN/AN/AN/AN/A
Mean positive reaction strengthN/AN/AN/AN/AN/A
Positive reaction rangeN/AN/AN/AN/AN/A
Total tested FrozenN/AN/AN/AN/A342
Mean positive reaction strengthN/AN/AN/AN/A7.1
Positive reaction rangeN/AN/AN/AN/A1-10
Clinical site Totals
Total tested Fresh012140N/A
Mean positive reaction strengthN/AN/AN/A7.0N/A
Positive reaction rangeN/AN/AN/A1-10N/A
Total tested Frozen031102342
Mean positive reaction strengthN/A8.0N/A8.07.1
Positive reaction rangeN/A1-10N/A1-101-10
Table 3. Patient age, sample storage statistics and mean positive reaction strengths
--------------------------------------------------------------------------------------------------

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Table 4. Patient gender statistics and mean positive reaction strengths
---------------------------------------------------------------------------
MaleFemaleNot defined
Clinical site 1
Total tested701240
Mean positive reaction strength5.66.7N/A
Positive reaction range1-101-10N/A
Clinical site 2
Total tested28270
Mean positive reaction strength8.27.9N/A
Positive reaction range1-101-10N/A
Clinical site 3
Total testedN/AN/A400
Mean positive reaction strengthN/AN/A7
Positive reaction rangeN/AN/A1-10
Clinical site Totals
Total tested98151400
Mean positive reaction strength6.67.17
Positive reaction range1-101-101-10

Sample comparison

Semi-solid or liquid (diarrheal) stools are more frequently encountered in patients with C. difficileassociated disease (CDAD). However, it may be necessary to test solid stool for the presence of toxin. Instructions for collecting, preparing and storing the three stool types are given in the instructions for inditions for our of consoling for specimens used in the clinical trial were semi-solid. Appropriate results were obtained with all three types.

Table 5. Stool sample type and mean positive reaction strengths

Stool Type
SolidSemi-solidLiquidNot defined
Total tested -- Clinical Site 1
Total tested23108630
Mean positive reaction strength7.05.66.7N/A
Positive reaction range1-101-101-10N/A
Total tested -- Clinical Site 2
Total tested2019160
Mean positive reaction strength7.27.89.7N/A
Positive reaction range1-101-101-10N/A
Total tested -- Clinical Site 3
Total tested121242060
Mean positive reaction strength37.57.1N/A
Positive reaction range1-31-91-10N/A
Total tested -- All Sites
Total tested552512850
Mean positive reaction strength6.96.97.1N/A
Positive reaction range1-101-101-10N/A

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Table 6. Stool sample storage parameters and mean positive reaction strengths
----------------------------------------------------------------------------------
Stool Type
FreshFrozenNot recorded
Total tested -- Clinical Site 1142520
Total tested142520
Mean positive reaction strength6.65.7N/A
Positive reaction range1-101-10N/A
Total tested -- Clinical Site 20550
Total tested0550
Mean positive reaction strengthN/A8.0N/A
Positive reaction rangeN/A1-10N/A
Total tested -- Clinical Site 303420
Total tested03420
Mean positive reaction strengthN/A7.1N/A
Positive reaction rangeN/AN/AN/A
Total tested -- All Sites1424490
Total tested1424490
Mean positive reaction strength6.67.2N/A
Positive reaction range1-101-10N/A

Clinical trial data summarized

The data collected during clinical trials is shown in the spreadsheets provided at the end of these sections. The results can be summarized as follows:

Table 7. Results of clinical evaluations

Clinical site 1ICTABReferenceBD ColorPACReferenceWampole
PosNegTotalPosNegTotalPosNegTotal
Cytotoxin Pos (Std)412433584338543
Cytotoxin Neg (Std)115015121491516145151
Total421521943715719444150194
95% CI
Clinical sensitivity41/43 (95.3%)89.1-100%35/43 (81.4%)38/43 (88.4%)
Clinical specificity150/151 (99.3%)97.4-100%149/151 (98.7%)145/151 (96.0%)
Predictive value positive test41/42 (97.6%)94.1-100%35/37 (94.6%)38/44 (86.4%)
Predictive value negative test150/152 (98.5%)97.4-100%149/157 (94.9%)145/150 (96.7%)
Clinical site 2ICTABReference OxoidReference PTAB
PosNegTotalPosNegTotalPosNegTotal
Cytotoxin Pos (Std)253282532826228
Cytotoxin Neg (Std)126271262732427
Total262955262955292655
95% CI
Clinical sensitivity25/28 (89.3%)77.2-100%25/28 (89.3%)26/28 (92.9%)
Clinical specificity26/27 (96.3%)88.2-100%26/27 (96.3%)24/27 (88.9%)
Predictive value positive test25/26 (96.2%)88.2-100%25/26 (96.2%)26/29 (89.7%)
Predictive value negative test26/29 (89.7%)78.2-100%26/29 (89.7%)24/26 (92.3%)

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Clinical site 3ICTABReferenceBD
PosNegTotalPosNegTotal
Cytotoxin Pos (Std)3403425934
Cytotoxin Neg (Std)530330811297308
Total3930334236306342
95% CI
Clinical sensitivity34/34 (100%)NA25/34 (71.4%)
Clinical specificity303/308 (98.3%)96.4-99.6%297/308 (96.4%)
Predictive value positive test34/39 (87.2%)75.2-98.8%25/36 (69.4%)
Predictive value negative test303/303 (100%)NA297/306 (97.1%)
Total Sites Combined Data - Comparison to StandardICTAB
PosNegTotal
Cytotoxin Pos (Std)1005105
Cytotoxin Neg (Std)7479486
Total107484591
95% CI
Clinical sensitivity100/105 (95.2%)90.9-99.1%
Clinical specificity479/486 (98.5%)98.0-100%
Predictive value positive test100/107 (93.5%)88.1-97.9%
Predictive value negative test479/484 (99.0%)98.2-99.8%

Combined data differentiated based on sample type

Prospective Samples
PosNegTotal
Cytotoxin Pos (Std)67572
Cytotoxin Neg (Std)2176178
Total69181250
95% CI
Clinical sensitivity67/72 (93.1%)87.1-98.9%
Clinical specificity176/178 (98.9%)97.6-100%
Predictive value positive test67/69 (97.1%)92.9-100%
Predictive value negative test176/181 (97.2%)94.5-99.5%
Retrospective Samples
PosNegTotal
Cytotoxin Pos (Std)33033
Cytotoxin Neg (Std)5303308
Total38303341
95% CI
Clinical sensitivity33/33 (100%)N/A
Clinical specificity303/308 (98.4%)96.4-99.6%
Predictive value positive test33/38 (86.8%)76.2-97.8%
Predictive value negative test303/303 (100%)N/A

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Characterization of samples producing discordant results

Samples producing discordant test results between ImmunoCard Toxins A& B and cytotoxin are listed Samples producing ulscordant test results betwoor immaries and first and the positive below. Three of the hee samples oldobined as infracts that were not neutralized in the cytotoxin assay until the specimens were diluted 1 in 10.

SampleNumberICTABResultCytotoxinResultCounted asICTABComment
1-32NegPosFNNo repeat testing performed
1-119NegPosFNNo repeat testing performed
1-270PosNegFPNo repeat testing performed
2-1NegPosFNNo repeat testing performed
2-2NegPosFNNo repeat testing performed
2-25NegPosFNNo repeat testing performed
2-41PosNegFPNo repeat testing performed
3-103PosNegFPStrong positive sample. Cytotoxin assay converted to positiveon repeat testing at 1:10 dilution
3-118PosNegFPStrong positive sample. Cytotoxin assay converted to positiveon repeat testing at 1:10 dilution
3-200PosNegFPCytotoxin assay remained negative on repeated testing
3-233PosNegFPNo repeat testing performed
3-241PosNegFPStrong positive sample. Cytotoxin assay converted to positiveon repeat testing at 1:10 dilution

Table 8. Samples producing discrepant results.

Legend: ICTAB ≤ ImmunoCard Toxins A & B, FN = false negative, FP = false positive

Reproducibility

Reproducibility panels, consisting of eight coded specimens were sent to the three clinical sites. Five of these r reproducilly partified by the predicate device Premier Toxins A & B as positive and one was at the limit of stamples were stablined by the produce a positive or negative or negative result. Even though the trial sites were instructed to grade reactions, there were no criteria regarding the strength of a positive reaction that was expected. As the data shows, there was 100% reproducibility/precision within a test site and between the test sites.

Clinical Site 1Clinical Site 2Clinical Site 3
Sample IDDay 1Day 2Day 3Day 1Day 2Day 3Day 1Day 2Day 3
1 LP212544223
2 LP223756665
3 MP566466556
4 MP778999678
5 HP10910891010108
6 N000000000
7 N000000000
8 Limit of detect333456344
Total positive score292832373841323434
Average positive score4.84.65.36.26.36.85.35.75.7
Percent correlation100100100100100100100100100

Table 9. Results with reproducibility test panels.

Legend: LP = low positive, MP = moderate positive, HP = high positive, N = negative,

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Analytical sensitivity

The analytical sensitivity of the assay was determined in tests using negative stool samples that had The arraying of the about the about has spure toxin A or pure toxin B. The assay limit of detection is been i spitca will varying our centralit noduced a positive reaction of grade 1 or more across three lots of ImmunoCard. The results of these studies showed the assay limit of detection is 3 ng/mL for both toxin A and toxin B.

ICTAB LotICTAB LotICTAB Lot
712050.002712050.003712050.004
Toxin AControlTestInterpControlTestInterpControlTestInterp
ng/mL
5.0041/2Pos71/2Pos92Pos
4.0041/2Pos71Pos92Pos
3.0041Pos71Pos91Pos
2.0041Pos71Pos91Pos
1.0040Neg71Pos90/1Pos
0.5040Neg70Neg90/1Pos
0.2530Neg70Neg90Neg
0.0020Neg70Neg90Neg
PCPass
NCPass
Endpoint2.001.002.00
Toxin B
ng/mL
3.0021Pos72Pos92Pos
2.0021Pos72Pos92Pos
1.0030/1Pos71/2Pos91/2Pos
0.5030/1Pos70/1Pos91Pos
0.2530Neg70Neg90/1Pos
0.12530Neg70Neg90Neg
0.062530Neg70Neg90Neg
0.0030Neg70Neg90Neg
PCPass
NCPass
Endpoint2.001.000.50

Table 10. Limit of detection testing.

High dose hook effect

There was no high dose hook effect observed in verification or clinical testing performed with this assay.

Clinical trial data shows that ImmunoCard Toxins A & B is substantially equivalent to the standard method (cytotoxicity) and to predicate devices currently approved to market in the United States.

CONCLUSIONS

ImmunoCard Toxins A & B meets all performance claims when used to test hurnan stool specimens from the general population.

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Image /page/15/Picture/1 description: The image shows the logo for the Department of Health & Human Services (HHS). The logo consists of a stylized human figure with three flowing lines representing health, services, and people. The figure is positioned to the right of the text "DEPARTMENT OF HEALTH & HUMAN SERVICES (USA)", which is arranged in a circular fashion around the figure.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

AUG 2 0 2004

Ms. Susan Rolih Vice President, Regulatory Affairs/Quality Assurance Meridian Bioscience, Inc. 3471 River Hills Drive Cincinnati, OH 45244

K041003 Re:

Trade/Device Name: Immuno Card® Toxins A & B Regulation Number: 21 CFR 866.2660 Regulation Name: Microorganism differentiation and identification device Regulatory Class: Class I Product Code: LLH Dated: July 21, 2004 Received: July 22, 2004

Dear Ms. Rolih:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).

{16}------------------------------------------------

Page 2

This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 594-3084. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.

Sincerely yours,

Saaxtys

Sally A. Hojvat, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

Enclosure

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Meridian Bioscience, Inc. Cincinnati, OH

INDICATIONS FOR USE (Amended 8/14/04)

510(K) Number (if known):

Device Name: ImmunoCard Toxins A& B

Indications For Use: ImmunoCard Toxins A & B is an in vitro diagnostic qualitative enzyme immunoassay to detect the presence of Clostridium difficile toxins A and B in human stool. The assay is used as an aid in the diagnosis of C. difficile associated disease.

Prescription Use _____________________________________________________________________________________________________________________________________________________________ (Part 21 CFR 801 Subpart D)

. .

AND/OR

Over-The-counter Use (21 CFR 807 Subpart C)

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of In Vitro Diagnostic Devices (OIVD)

Ferdinand Carlo

Division Sign-Off

8-1

Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) KC4 1003

§ 866.2660 Microorganism differentiation and identification device.

(a)
Identification. A microorganism differentiation and identification device is a device intended for medical purposes that consists of one or more components, such as differential culture media, biochemical reagents, and paper discs or paper strips impregnated with test reagents, that are usually contained in individual compartments and used to differentiate and identify selected microorganisms. The device aids in the diagnosis of disease.(b)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.