(85 days)
The IMDx C. difficile for Abbott m2000 assay is an in vitro diagnostic assay that uses real-time polymerase chain reaction (PCR) amplification for the qualitative detection of nucleic acids encoding the toxin A gene (tcdA) and toxin B gene (tcdB ) sequences of toxigenic strains of Clostridium difficile in human liquid or soft stool specimens collected from patients suspected of having symptoms of Clostridium difficile infection.
The assay is intended to be performed on the Abbott m2000 System (which comprises the Abbott m2000sp and m2000rt instruments) and is indicated for use as an aid in the diagnosis of Clostridium difficile infection. The test is intended to be used directly on liquid or soft stool specimens (unpreserved stool, or stool preserved in Cary Blair transport medium). Negative results do not preclude toxigenic C. difficile infection and should not be used as the sole basis for treatment or other patient management decisions. The IMDx C. difficile for Abbott m2000 assay is intended for professional use. The device is not intended for point-of-care use.
The IMDx C. difficile for Abbott m2000 assay uses PCR to generate amplified product from the tcdA and tcdB/tcdBv genes in toxigenic C. difficile DNA in clinical specimens. The presence of a toxigenic C. difficile target sequence is indicated by the fluorescent signal generated through the use of fluorescently labeled oligonucleotide probes on the Abbott m2000rt instrument. The probes do not generate a signal unless they are specifically bound to the amplified product. The amplification cycle at which fluorescent signal is detected by the Abbott m2000rt is inversely proportional to the toxigenic C. difficile DNA target concentration present in the original specimen. A bacterial species unrelated to toxigenic C. difficile is introduced into each specimen during sample preparation to serve as a process control. The process control bacteria are lysed simultaneously with toxigenic C. difficile in the specimen, and amplified in the same reaction as the C. difficile targets using PCR, and serve to demonstrate that the entire assay process has proceeded correctly for each specimen.
Here's a breakdown of the acceptance criteria and the study details for the IMDx C. difficile for Abbott m2000 assay, based on the provided 510(k) summary:
Acceptance Criteria and Device Performance
The acceptance criteria are not explicitly stated in a defined section. However, based on the "Clinical Performance Characteristics" section, we can infer the acceptance criteria are related to the clinical agreement (Sensitivity, Specificity, Positive Predictive Value, and Negative Predictive Value) when compared to the Bartels® Cytotoxicity Assay for Clostridium difficile Toxin.
Here's a summary of the reported device performance:
| Performance Metric | Acceptance Criteria (Inferred) | Reported Performance (Unpreserved Stool) | Reported Performance (Cary Blair Preserved Stool) |
|---|---|---|---|
| Clinical Sensitivity | Not explicitly stated | 86.1% (95% CI: 79.4% - 90.9%) | 91.3% (95% CI: 73.2% - 97.6%) |
| Clinical Specificity | Not explicitly stated | 92.5% (95% CI: 90.7% - 93.9%) | 93.5% (95% CI: 90.5% - 95.7%) |
| Positive Predictive Value | Not explicitly stated | 59.9% (95% CI: 52.9% - 66.5%) | 47.7% (95% CI: 33.8% - 62.1%) |
| Negative Predictive Value | Not explicitly stated | 98.1% (95% CI: 97.0% - 98.8%) | 99.4% (95% CI: 97.8% - 99.8%) |
Note: For analytical performance metrics like "Precision/Reproducibility" and "Analytical Sensitivity (LoD)", the tables present the results, but specific numerical acceptance criteria (e.g., minimum % agreement for reproducibility or maximum CFU/mL for LoD) are not explicitly outlined as "acceptance criteria." However, the data presented implies that these results were deemed acceptable to demonstrate adequate analytical performance. For example, for "Precision/Reproducibility", achieving high percentage agreement, especially for positive and low positive samples, suggests successful criteria were met.
Study Details
-
Sample sizes used for the test set and the data provenance:
- Total Test Set Sample Size: 1,565 specimens.
- 1,186 unpreserved stool specimens
- 379 Cary Blair preserved stool specimens
- Data Provenance: The study was conducted at "seven (7) geographically diverse locations within the United States from 2011 to 2013." This indicates prospective data collection for a clinical trial.
- Total Test Set Sample Size: 1,565 specimens.
-
Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience):
- The document does not specify the number of experts or their qualifications for establishing the ground truth. The ground truth was established by a reference assay.
-
Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- The document implies a form of discrepancy analysis rather than adjudication by multiple human readers for initial ground truth establishment. For discrepant results between the IMDx C. difficile for Abbott m2000 assay and the Bartels® Cytotoxicity Assay, "sequencing" was used to resolve some of these discrepancies (e.g., for unpreserved stool: 16 samples were sequenced, 13 resolved as negative, 3 remained discrepant; 53 samples were sequenced, 40 resolved as positive, 9 remained discrepant, 4 indeterminate). This suggests a molecular method was used for further investigation of conflicting results, rather than expert consensus on the initial test.
-
If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- No, a multi-reader multi-case (MRMC) comparative effectiveness study was not performed. This device is an in vitro diagnostic assay for molecular detection, not an imaging or interpretive device that would typically involve human readers and AI assistance.
-
If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, a standalone performance study was done. The "Clinical Performance Characteristics" section reports the performance of the IMDx C. difficile for Abbott m2000 assay (the algorithm/device) directly against the reference method. There is no mention of human interpretation influencing the assay's output.
-
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The primary ground truth was established by comparison to the Bartels® Cytotoxicity Assay for Clostridium difficile Toxin. For discrepant results, sequencing was used for further resolution, serving as a secondary, more definitive ground truth for those specific cases.
-
The sample size for the training set:
- The document does not explicitly state a sample size for a training set. This is a molecular diagnostic assay, and while it uses PCR amplification, the summary focuses on analytical validation and clinical validation against a reference method, rather than a machine learning model that would typically have distinct training and test sets in the same way. The analytical studies (e.g., LoD, reactivity, cross-reactivity) might be seen as foundational "training" for the assay's design, but not in the sense of a machine learning training set with labeled data.
-
How the ground truth for the training set was established:
- As mentioned above, a "training set" in the context of machine learning is not described. For the development and analytical validation of the assay, ground truth would have been established through controlled laboratory experiments using well-characterized C. difficile strains and other microorganisms, as described in the Analytical Reactivity and Cross-Reactivity sections. The document indicates these strains were identified and confirmed (e.g., ATCC strains), which serves as their established "ground truth" for analytical purposes.
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K/32235
510(k) Summary
October 1, 2013 Date of Summary:
Product Name
Sponsor
IMDx C. difficile for Abbott m2000
Intelligent Medical Devices, Inc. 19 Blackstone Street Cambridge, MA 02139
Correspondent
MDC Associates, LLC Fran White, Regulatory Consultant 180 Cabot Street Beverly, MA 01915
OCT
1 1 2013
Device Identification
IMDx C. difficile for Abbott m2000 Trade or Proprietary Name: C. difficile nucleic acid amplification test assay Common or Usual Name: Product Code: OZN Regulation Section: 21 CFR 866.3130 Product Classification: Class II
Intended Use
The IMDx C. difficile for Abbott m2000 assay is an in vitro diagnostic assay that uses real-time polymerase chain reaction (PCR) amplification for the qualitative detection of nucleic acids encoding the toxin A gene (tcd4) and toxin B gene (tcdB ) sequences of toxigenic strains of Clostridium difficile in human liquid or soft stool specimens collected from patients suspected of having symptoms of Clostridium difficile infection.
The assay is intended to be performed on the Abbott m2000 System (which comprises the Abbott m2000sp and m2000rt instruments) and is indicated for use as an aid in the diagnosis of Clostridium difficile infection. The test is intended to be used directly on liquid or soft stool specimens (unpreserved stool preserved in Cary Blair transport medium). Negative results do not preclude toxigenic C. difficile infection and should not be used as the sole basis for treatment or other patient management decisions. The IMDx C. difficile for Abbott m2000 assay is intended for professional use. The device is not intended for point-of-care use.
Device Description
The IMDx C. difficile for Abbott m2000 assay uses PCR to generate amplified product from the tedd and tedBledBv genes in toxigenic C. difficile DNA in clinical specimens. The presence of a toxigenic C. difficile target sequence is indicated by the fluorescent signal generated through the use of fluorescently labeled oligonucleotide probes on the Abbott m2000rt instrument. The probes do not generate a signal unless they are specifically bound to the amplified product. The amplification cycle at which fluorescent signal is detected by the Abbott m2000rt is inversely proportional to the toxigenic C. difficile DNA target concentration present in the original specimen. A bacterial species unrelated to toxigenic C. difficile is introduced into each specimen during sample preparation to serve as a process control. The process control bacteria are lysed simultaneously with toxigenic C. difficile in the specimen,
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and amplified in the same reaction as the C. difficile targets using PCR, and serve to demonstrate that the entire assay process has proceeded correctly for each specimen.
Substantial Equivalency
IMDx C. difficile for Abbott m2000 is substantially equivalent to theQuidel AmpliVue™ C. difficile assay (K123355). Table 1 compares the characteristics of the IMDx C. difficile assay (New Device) and the Quidel Amplivue C. difficile assay(Predicate Device).
| Similarities | ||
|---|---|---|
| Characteristic | Predicate DeviceQuidel Amplivue C. difficile assay | IMDx C. difficile forAbbott m2000 Assay |
| 510(k) | K123355 | K132235 |
| Regulation | 866.3130 | 866.3130 |
| Product Code | OZN | OZN |
| Device Class | Class II | Class II |
| Intended use | The AmpliVueTM C. difficile Assay is an invitro diagnostic test for the direct, qualitativedetection of the Clostridium difficile Toxin Agene ( tcdA ) in unformed stool specimens ofpatients suspected of having Clostridiumdifficile-associated disease (CDAD). TheAmpliVueTM C. difficile Assay is intended foruse as an aid in diagnosis of CDAD. The assayutilizes helicase-dependlent amplification(HDA) for the amplification of a highlyconserved fragment of the Toxin A genesequence and a self-contained disposableamplicon detection device that allows formanual evaluation of assay results. | The IMDx C. difficile for Abbott m2000 assay isan in vitro diagnostic assay that uses real-timepolymerase chain reaction (PCR) amplificationfor the qualitative detection of nucleic acidsencoding the toxin A gene ( tcdA ) and toxin Bgene ( tcdB ) sequences of toxigenic strains ofClostridium difficile in human liquid or soft stoolspecimens collected from patients suspected ofhaving symptoms of Clostridium difficileinfection.The assay is intended to be performed on theAbbott m2000 System (which comprises theAbbott m2000sp and m2000rt instruments)and is indicated for use as an aid in thediagnosis of Clostridium difficile infection.The test is intended to be used directly onliquid or soft stool specimens (unpreservedstool, or stool preserved in Cary Blairtransport medium). Negative results do notpreclude toxigenic C. difficile infection andshould not be used as the sole basis fortreatment or other patient managementdecisions. The IMDx C. difficile for Abbottm2000 assay is intended for professional use.The device is not intended for point-of-careuse. |
| Sample type | Unformed stool | Soft or liquid stool (unpreserved stool, or stoolpreserved in Cary Blair transport medium). |
| Test Principle | Nucleic acid amplification | Real-time PCR DNA amplification |
| Analyte | Toxin A gene ( tcdA ) | Toxin A gene ( tcdA )Toxin B genes ( tcdB and tcdBv ) |
| Controls | Process Control included in the kitPositive and Negative Controls not included inkit; separate control kit available for sale | Positive Control, Negative Control andProcess Control included in the kit |
| Differences | ||
| Characteristic | Predicate DeviceQuidel Amplivue C. difficile assay | IMDx C. difficile forAbbott m2000 Assay |
| Instrument | Self-contained, disposable cassette with anamplicon cartridge and detection chamber | Assay uses the Abbott m2000 System foramplification and detection |
| ExtractionMethod | Manual | Automated on the Abbott m2000sp |
Table 1. Substantial Equivalence
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These differences do not affect substantial equivalence of the IMDx C. difficile for Abbott m2000 and Quidel Amplivue C. difficile assays. Both assays detect C. difficile nucleic acids from soft or liquid unformed stool specimens and have comparable intended uses. The differences noted above do not impact the intended use and do not raise questions as to the safety and effectiveness of the test (new) device.
Performance Characteristics
Analytical Performance
Precision/Reproducibility:
Assay precision was measured in four independent studies: within laboratory repeatability, instrument-to-instrument repeatability, lot-to-lot repeatability, and site reproducibility using a seven-membered panel consisting of two C. difficile strains at concentrations representing a positive specimen (2-3X LoD), a low positive specimen (1X LoD), a high negative specimen (0.05X LoD), and a negative specimen.
| PanelMember | Reproducibility | Lot-to-Lot | m2000sptom2000sp | m2000rttom2000rt | Repeatability | Overall | |
|---|---|---|---|---|---|---|---|
| C. difficile1470 tcdB -variant(ATCC43598) | HighNegative | 86/106(81.1%) | 15/18(83.3%) | 17/18(94.4%) | 16/18(88.9%) | 61/72(84.7%) | 195/232(84.1%) |
| LowPositive | 107/107(100.0%) | 18/18(100.0%) | 18/18(100.0%) | 18/18(100.0%) | 71/72(100.0%) | 232/233(99.6%) | |
| Positive | 108/108(100.0%) | 18/18(100.0%) | 18/18(100.0%) | 18/18(100.0%) | 72/72(100.0%) | 234/234(100.0%) | |
| C. difficileNAP-1(ATCCBAA-1870) | HighNegative | 92/106(86.8%) | 12/17(70.6%) | 12/18(66.7%) | 13/18(72.2%) | 57/70(81.4%) | 186/229(81.2%) |
| LowPositive | 106/107(99.1%) | 18/18(100.0%) | 17/17(100.0%) | 18/18(100.0%) | 70/71(98.6%) | 229/231(99.1%) | |
| Positive | 110/110(100.0%) | 18/18(100.0%) | 18/18(100.0%) | 18/18(100.0%) | 72/72(100.0%) | 236/236(100.0%) | |
| Negative | 105/105(100.0%) | 18/18(100.0%) | 18/18(100.0%) | 18/18(100.0%) | 72/72(100.0%) | 231/231(100.0%) |
Table 2. Summary of % Agreement for Precision Studies.
Analytical Sensitivity (Limit of Detection)
The LoD is defined as the toxigenic C. difficile bacterial titer (CFU/mL) detected with a probability of 95% or greater. Three strains of C. difficile were used to determine the assay LoD for unpreserved stool specimens and stool specimens preserved in Cary Blair transport media. The results, representative of the analytical sensitivity of the IMDx C. difficile for Abbott m2000 assay, are summarized in Table 3.
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Table 3. Limit of Detection.
| Strain | LoDUnpreserved Stool | LoDCary-Blair Preserved Stool |
|---|---|---|
| C. difficile ATCC 43255Strain: VPI10463 (toxinotype 0) | 337 CFU/mL | 463 CFU/mL |
| C. difficile ATCC 43598Strain: 1470 (tcdB-variant) | 256 CFU/mL | 861 CFU/mL |
| C. difficile ATCC BAA-1870Strain: 4118 (BI/NAP1/027) | 67 CFU/mL | 134 CFU/mL |
Analytical Reactivity
A total of 31 different toxigenic C. difficile strains were tested to determine if they were detected by the IMDx C. difficile for Abbott m2000 assay. Strains were tested at a concentration of approximately 2-3X LoD, and were run in triplicate. Strains were considered to be detected if all 3 replicates were detected. All strains were detected.
Cross Reactivity & Microbial Interference
The IMDx C. difficile for Abbott m2000 assay was evaluated for potential cross reactivity and/or interference using a panel of 120 viruses and microorganisms (see Table 4). Bacteria were tested at a concentration of ≥ 1 × 10° CFU/mL, and viruses at a concentration of ≥ 1 × 10° TCID30/mL. None of the organisms tested were found to cross-react or interfere with the IMDx C. difficile for Abbott m2000 assay.
| Organism | Strain ID | Organism | Strain ID |
|---|---|---|---|
| Abiotrophia defectiva | ATCC 49176 | Enterococcus faecalis vanB | ATCC 51299 |
| Acinetobacter baumannii | ATCC19606 | Enterococcus faecium vanA | ATCC 700221 |
| Acinetobacter twoffii | ATCC17925 | Enterococcus gallinarum vanC | ATCC 49573 |
| Adenovirus (Type 40) | ZMC 0810084CF | Enterococcus hirae | ATCC 8043 |
| Aeromonas hydrophila | ZMC 0601715 | Enterococcus raffinosus | ATCC 49427 |
| Alcaligenes faecalis subsp. faecalis | ATCC 15554 | Enterovirus (Type 71) | ZMC 0810047CF |
| Anaerococcus tetradius | ATCC 35098 | Escherichia coli | ATCC 23511 |
| Bacillus cereus | ATCC 11778 | Escherichia coli 0157 | ZMC 0801622 |
| Bacillus cereus | ATCC 13472 | Escherichia fergusonii | ATCC 35469 |
| Bacteroides caccae | ATCC 43185 | Escherichia hermannii | ATCC 33650 |
| Bacteroides stercoris | ATCC 43183 | Fusobacterium varium | ATCC 8501 |
| Bifidobacterium adolescentis | ATCC 15703 | Gardnerella vaginalis | ATCC 14019 |
| Campylobacter coli | ATCC 43479 | Gemella morbillorum | ATCC 27824 |
| Campylobacter jejuni subsp jejuni | ATCC 33292 | Hafnia alvei | ATCC 13337 |
| Candida albicans | ATCC 10231 | Helicobacter pylori | ZMC 0601486; Z40 |
| Candida catenulata | ATCC 10565 | Homo sapiens | ATCC MGC-15492 |
| Cedecea davisae | ATCC 33431 | Klebsiella oxytoca | ATCC 33496 |
| Chlamydia trachomatis | ZMC D-UW3; Z054 | Klebsiella pneumoniae subsp.pneumoniae | ATCC 13883 |
| Citrobacter amalonaticus | ATCC 25405 | Lactobacillus acidophilus | ZMC 0601540 |
| Organism | Strain ID | Organism | Strain ID |
| Citrobacter freundii | ATCC 8090 | Lactobacillus reuteri | ATCC 23272 |
| Citrobacter koseri | ZMC 0601745 | Lactococcus lactis subsp. lactis | ATCC 11454 |
| Citrobacter sedlakii | ATCC 51115 | Leminorela grimontii | ATCC 33999 |
| Clostridium beijerinckii | ATCC 8260 | Listeria grayi | ATCC 19120 |
| Clostridium bifermentans | ATCC 638 | Listeria innocua | ATCC 33090 |
| Clostridium bolteae | ATCC BAA-613 | Listeria monocytogenes | ZMC 0801543 |
| Clostridium butyricum | ATCC 19398 | Norovirus | ZMC 0810087CF |
| Clostridium chauvoei | ATCC 11957 | Peptoniphilus asaccharolyticus | ATCC 14963 |
| Clostridium difficile (non-toxigenic) | ATCC 43593 | Peptostreptococcus anaerobius | ATCC 27337 |
| Clostridium difficile (non-toxigenic) | ATCC 43601 | Plesiomonas shigelloides | ATCC 14029 |
| Clostridium fallax | ATCC 19400 | Porphyromonas asaccharolytica | ATCC 25260 |
| Clostridium haemolyticum | ATCC 9656 | Prevotella melaninogenica | ATCC 25845 |
| Clostridium histolyticum | ATCC 19401 | Proteus mirabilis | ATCC 25933 |
| Clostridium innocuum | ATCC 14501 | Proteus penneri | ZMC 0601589 |
| Clostridium nexile | ATCC 27757 | Providencia alcalifaciens | ATCC 9886 |
| Clostridium novyi | ATCC 19402 | Providencia rettgeri | ATCC 9250 |
| Clostridium orbiscindens | ATCC 49531 | Providencia stuartii | ATCC 33672 |
| Clostridium paraputrificum | ATCC 25780 | Pseudomonas aeruginosa | ATCC 35554 |
| Clostridium perfringens | ZMC 0601585 | Pseudomonas putida | ZMC 0601722 |
| Clostridium ramosum | ATCC 25582 | Rotavirus | ZMC MA-104 |
| Clostridium scindens | ATCC 35704 | Ruminococcus bromii | ATCC 27255 |
| Clostridium sordellii | ATCC 9714 | Salmonella choleraesuis subsp.choleraesuis | ATCC 7001 |
| Clostridium sphenoides | ATCC 19403 | Salmonella enterica subsp. enterica | ATCC 14028 |
| Clostridium spiroforme | ATCC 29900 | Salmonella enterica subsp. arizonae | ATCC 13314 |
| Clostridium sporogenes | ATCC 15579 | Serratia liquefaciens | ATCC 27592 |
| Clostridium symbiosum | ATCC 14940 | Serratia marcescens | ATCC 13880 |
| Clostridium tertium | ATCC 14573 | Shigella boydii | ATCC 9207 |
| Clostridium tetani | ATCC 19406 | Shigella dysenteriae | ZMC 0601609 |
| Collinsella aerofaciens | ATCC 25986 | Shigella sonnei | ATCC 29930 |
| Corynebacterium genitalium LSPQ 3583 | ATCC 33798 | Staphylococcus aureus | ZMC 0601675 |
| Coxsackie virus (Type B4) | ZMC 0810075CF | Staphylococcus epidermidis | ATCC 14990 |
| Cytomegalovirus (AD-169) | ZMC 0810003CF | Stenotrophomonas maltophilia | ATCC 13637 |
| Desulfovibrio piger | ATCC 29098 | Streptococcus agalactiae | ZMC 0601545 |
| Echovirus (Type 11) | ZMC 0810023CF | Streptococcus dysgalactiae | ATCC 43078 |
| Edwardsiella tarda | ATCC 15947 | Streptococcus intermedius | ATCC 27335 |
| Eggerthella lenta | ATCC 25559 | Streptococcus uberis | ATCC 19436 |
| Enterobacter aerogenes | ATCC 13048 | Veillonella parvula | ATCC 10790 |
| Enterobacter cloacae | ATCC 13047 | Vibrio cholerae | ATCC 25870 |
| Enterococcus casseliflavus | ZMC 0601565 | Vibrio parahaemolyticus | ATCC 17802 |
| Enterococcus cecorum | ATCC 43198 | Yersinia bercovieri | ATCC 43970 |
| Enterococcus dispar | ATCC 51266 | Yersinia rohdei | ATCC 43380 |
Table 4. Cross Reactivity and Microbial Interference.
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IMDx C. difficile for Abbott m2000
K132235 - 510(k) Summary
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Interfering Substances
The IMDx C. difficile for Abbott m2000 assay was challenged with twenty-three (23) substances that may be present in stool specimens. The substances included: anti-fungal/antiitch vaginal cream, suppositories, anti-hemorrhoid creams/ointments, antacids, enemas, condoms with spermicidal lubricant, anti-diartheal medication, laxatives, antibiotics (oral and topical), non-steroidal anti-inflammatory medications, moist towelettes, fecal components (e.g., blood, mucus, fecal fats), and MRI contrast agent. No assay interference was observed for any of the substances.
Target Carryover Study
Five assay runs were performed with alternating high positive and negative samples. A single cross-contamination carryover event was observed in one of the five runs, generating a carryover rate of 0.4% (1/235).
Clinical Performance Characteristics
The performance of the IMDx C. difficile for Abbott m2000 assay was evaluated at seven (7) geographically diverse locations within the United States from 2011 to 2013. A total of 1,565 (1186 unpreserved stool, 379 preserved stool) specimens were included in the final data set and analyzed for product performance as compared to results obtained from Bartels® Cytotoxicity Assay for Clostridium difficile Toxin (Trinity Biotech, Carlsbad, CA [Distributed by Diagnostic Hybrids, Athens, OH]).
| Bartels/Cytotoxin | ||||||
|---|---|---|---|---|---|---|
| Pos | Neg | Total | ||||
| IMDx C.difficile for | Pos | 118 | 79** | 197 | ||
| Abbott m2000 | Neg | 19* | 970 | 989 | ||
| Total | 137 | 1049 | 1186 | |||
| 95% CI | ||||||
| Sensitivity | 86.1% | (79.4% - 90.9%) | ||||
| Specificity | 92.5% | (90.7% - 93.9%) | ||||
| Positive Predictive Value | 59.9% | (52.9% - 66.5%) | ||||
| Negative Predictive Value | 98.1% | (97.0% - 98.8%) | ||||
| Prevalence | 11.6% |
Table 5. Clinical Agreement Summary: Unpreserved Stool
· 16 samples were sequenced, 13 were resolved as negative and 3 remained discrepant.
· 53 samples were sequenced, 40 were resolved as positive, 9 remained discrepant and 4 had indeterminate results.
| Table 6. Clinical Agreement Summary: Stool Preserved in Cary Blair Transport Medium. | ||||
|---|---|---|---|---|
| -------------------------------------------------------------------------------------- | -- | -- | -- | -- |
| Bartels/Cytotoxin | ||||
|---|---|---|---|---|
| Pos | Neg | Total | ||
| IMDx C.difficile forAbbott m2000 | Pos | 21 | 23** | 44 |
| Neg | 2* | 333 | 335 | |
| Total | 23 | 356 | 379 | |
| Sensitivity | 91.3% | 95% CI (73.2%-97.6%) | ||
| Specificity | 93.5% | (90.5%-95.7%) | ||
| Positive Predictive Value | 47.7% | (33.8%-62.1%) | ||
| Negative Predictive Value | 99.4% | (97.8%-99.8%) | ||
| Prevalence | 6.1% |
· 2 samples were sequenced, 1 was resolved as negative and I remained discrepant.
** 20 samples were sequenced, 12 were resolved as positive and 8 remained discrepant.
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Study Results by age
Subjects ranged in age from <1 to 112 years old. The table below shows the number of subjects by age.
| Age and Gender Distribution of IMDx C. difficile for Abbott m2000 Assay Positive Results | ||||||
|---|---|---|---|---|---|---|
| Age Group | Specimen Type & Gender*# Positive / # Enrolled(Prevalence [%]) | |||||
| Raw/Fresh (Unpreserved Stool) | Cary-Blair (Preserved Stool) | |||||
| Male | Female | Total | Male | Female | Total (%) | |
| Unknown age | 0/1(0.0%) | 0/1(0.0%) | 0/5§(0.0%) | 0/0(0.0%) | 0/0(0.0%) | 0/0(0.0%) |
| Infant(<2 yrs) | 0/4(0.0%) | 2/2(100.0%) | 2/6(33.3%) | 0/3(0.0%) | 0/0(0.0%) | 0/3(0.0%) |
| Child(≥2 to <12 yrs) | 1/7(14.3%) | 1/9(11.1%) | 2/16(12.5%) | 2/6(33.3%) | 0/3(0.0%) | 2/9(22.2%) |
| Adolescent(≥12 to <18 yrs) | 0/8(0.0%) | 1/6(16.7%) | 1/14(7.1%) | 0/2(0.0%) | 0/4(0.0%) | 0/6(0.0%) |
| Transitional Adolescent(≥18 to ≤21 yrs) | 2/7(28.6%) | 3/15(20.0%) | 5/22(22.7%) | 2/4(50.0%) | 1/8(12.5%) | 3/12(25.0%) |
| Adult(>21 to ≤59 yrs) | 38/273(13.9%) | 40/297(13.5%) | 78/571†(13.7%) | 11/82(13.4%) | 8/105(7.6%) | 19/187(10.2%) |
| Sr. Adult(> 60 yrs) | 47/242(19.4%) | 62/310(20.0%) | 109/552(19.7%) | 9/68(13.2%) | 11/94(11.7%) | 20/162(12.3%) |
| Total | 88/542(16.2%) | 109/640(17.0%) | 197/1,186(16.6%) | 24/165(14.5%) | 20/214(9.3%) | 44/379(11.6%) |
| Table 7. Study Population Age and Gender Distribution |
|---|
| ------------------------------------------------------- |
.
- Prevalence based on C. difficile positives with the IMDx C. difficile for Abbott m2000 assay.
6The gender of three individuals in this age group was not known.
TThe gender of one individual in this age group was not known.
Conclusions
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
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Image /page/7/Picture/0 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized eagle with three lines representing its body and wings. The eagle is facing to the right. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" is arranged in a circular pattern around the eagle.
DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
October 11, 2013
INTELLIGENT MEDICAL DEVICES, INC. C/O FRAN WHITE REGULATORY CONSULTANT MDC ASSOCIATES 180 CABOT STREET BEVERLY MA 01915
Re: K132235
Trade/Device Name: IMDx C.difficile for Abbott m2000 Regulation Number: 21 CFR 866.3130 Regulation Name: C. difficile Nucleic Acid Amplification Test Assay Regulatory Class: II Product Code: OZN, OOI Dated: July 17, 2013 Received: July 18, 2013
Dear Ms. White:
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. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. 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); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638 2041 or (301) 796-7100 or at its Internet address http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to
http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
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) 796-7100 or at its Internet address http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm.
Sincerely yours.
Sally A. Hojvat -S
Sally A. Hojvat, M.Sc., Ph.D. Director, Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
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Indications for Use
K132235 510(k) Number:
Device Name:
IMDx C. difficile for Abbott m2000
Indications for Use:
The IMDx C. difficile for Abbott m2000 assay is an in vitro diagnostic assay that uses real-time polymerase chain reaction (PCR) amplification for the qualitative detection of nucleic acids encoding the toxin A gene (tcdA) and toxin B gene (tcdB ) sequences of toxigenic strains of Clostridium difficile in human liquid or soft stool specimens collected from patients suspected of having symptoms of Clostridium difficile infection.
The assay is intended to be performed on the Abbott m2000 System (which comprises the Abbott m2000sp and m2000rt instruments) and is indicated for use as an aid in the diagnosis of Clostridium difficile infection. The test is intended to be used directly on liquid or soft stool specimens (unpreserved stool, or stool preserved in Cary Blair transport medium). Negative results do not preclude toxigenic C. difficile infection and should not be used as the sole basis for treatment or other patient management decisions. The IMDx C. difficile for Abbott m2000 assay is intended for professional use. The device is not intended for point-of-care use.
Prescription Use X (Part 21 CFR 801 Subpart D)
AND/OR
Over-The-Counter Use (21 CFR 801 Subpart C)
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE OF NEEDED)
Concurrence of CDRH, Office of In Vitro Diagnostics and Radiological Health (OIR)
Ribhi Shawar
2013.10.10 13:41:04'00'
§ 866.3130 Clostridium difficile toxin gene amplification assay.
(a)
Identification. AClostridium difficile toxin gene amplification assay is a device that consists of reagents for the amplification and detection of target sequences inClostridium difficile toxin genes in fecal specimens from patients suspected of havingClostridium difficile infection (CDI). The detection of clostridial toxin genes, in conjunction with other laboratory tests, aids in the clinical laboratory diagnosis of CDI caused byClostridium difficile. (b)
Classification. Class II (special controls). The special controls are set forth in FDA's guideline document entitled: “Class II Special Controls Guideline: Toxin Gene Amplification Assays for the Detection ofClostridium difficile; Guideline for Industry and Food and Drug Administration Staff.” See § 866.1(e) for information on obtaining this document.