(90 days)
Not Found
No
The device description details a manual, visually interpreted immunoassay with no mention of computational analysis, image processing, or AI/ML terms.
No
Explanation: This device is an in vitro diagnostic test for detecting a pathogen, not a device used to treat or prevent a disease directly.
Yes
The "Intended Use / Indications for Use" section explicitly states that the device is "FOR IN VITRO DIAGNOSTIC USE" and is intended to be "an aid in the diagnosis of E. histolytica gastrointestinal infection."
No
The device description clearly outlines a physical, single-use cassette with immobilized antibodies, a conjugate, diluent, wash buffer, and substrate. The test involves adding a sample to a tube, transferring it to the cassette, incubating, washing, and adding substrate, with visual interpretation of a color change. This is a hardware-based in vitro diagnostic test, not a software-only device.
Yes, this device is an IVD (In Vitro Diagnostic).
The document explicitly states in the "Intended Use / Indications for Use" section: FOR IN VITRO DIAGNOSTIC USE.
Furthermore, the description of the device and its intended use aligns with the definition of an in vitro diagnostic device, which is used to examine specimens taken from the human body to provide information for the diagnosis, prevention, or treatment of a disease or condition. In this case, the device tests human fecal specimens to aid in the diagnosis of E. histolytica gastrointestinal infection.
N/A
Intended Use / Indications for Use
The TECHLAB E. HISTOLYTICA QUIK CHEK™ test is a rapid membrane enzyme immunoassay for the qualitative detection of adhesin from Entamoeba histolytica in a single use cassette. It is intended for use with human fecal specimens from patients with diarrhea or dysentery as an aid in the diagnosis of E. histolytica gastrointestinal infection. Test results should be considered in conjunction with patient history.
FOR IN VITRO DIAGNOSTIC USE
Product codes (comma separated list FDA assigned to the subject device)
KHW
Device Description
The E. HISTOLYTICA QUIK CHEK™ test uses antibodies to adhesin. The device contains a Reaction Window with two vertical lines of immobilized antibodies. The test line ("T") contains monoclonal antibodies specific for E. histolytica adhesin. The control line ("C") contains antibodies to horseradish peroxidase (HRP). The Conjugate consists of polyclonal antibodies to E. histolytica adhesin coupled to horseradish peroxidase. To perform the test, the sample is added to a tube containing a mixture of Diluent and Conjugate. The diluted sample-conjugate mixture is added to the Sample Well and the device is allowed to incubate at room temperature for 15 minutes. During the incubation, E. histolytica adhesin in the samples bind to the antibodyperoxidase conjugate. The antigen-antibody complexes migrate through a filter pad to a membrane where they are captured by the immobilized antibodies in the Reaction Window is subsequently washed with Wash Buffer, and the test is developed with the addition of Substrate. After a 10 minute incubation period, the "T" reaction is examined visually for the appearance of a vertical blue line on the "T" side of the Reaction Window. A blue line indicates a positive test. A positive "C" reaction, indicated by a vertical blue line on the "C" side of the Reaction Window, monitors/confirms that the sample and reagents were added correctly, the reagents were active at the time of performing the assay, and that the sample migrated properly through the Membrane Device. It also confirms the reactivity of the other reagents associated with the assay.
Mentions image processing
Not Found
Mentions AI, DNN, or ML
Not Found
Input Imaging Modality
Not Found
Anatomical Site
Gastrointestinal
Indicated Patient Age Range
Not Found
Intended User / Care Setting
Not Found
Description of the training set, sample size, data source, and annotation protocol
Not Found
Description of the test set, sample size, data source, and annotation protocol
The performance of the E. HISTOLYTICA QUIK CHEK™ test was evaluated at 3 independent sites. A total of 851 fecal samples were evaluated and included 96 retrospective samples. Age information was available for 851 patients. Of the 851 patients. 18.9% were ≤ 20 years. Sex information was available for 851 patients, and 42.7% were male and 57.3% were female.
The Composite Reference Method (CRM) results were determined as follows:
| Microscopy | FDA cleared
multiplex NAAT test | Alternate PCR with
sequencing | CRM Result |
|------------|------------------------------------|----------------------------------|------------|
| Pos | Pos | Pos | Pos |
| Pos | Pos | Neg | Neg |
| Pos | Neg | Pos | Pos |
| Pos | Neg | Neg | Neg |
| Neg | Pos | Pos | Pos |
| Neg | Pos | Neg | Neg |
| Neg | Neg | N/A | Neg |
For the CRM result with Microscopy negative and FDA cleared multiplex NAAT test negative, no further testing was required.
Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Study Type: Clinical Performance Study (Prospective and Retrospective)
Sample Size: N = 755 prospective samples, N = 96 retrospective samples. Total 851 fecal samples.
Key Results:
Prospective Samples (N = 755):
- Sensitivity: 40.0% (95% Confidence Limits: 7.3% - 83.0%)
- Specificity: 100% (95% Confidence Limits: 99.4% - 100%)
- Predictive Positive Value: 100% (95% Confidence Limits: 19.8% - 100%)
- Predictive Negative Value: 99.6% (95% Confidence Limits: 98.7% - 99.9%)
- All three of the false negative results were PCR positive and antigen negative.
Retrospective Samples (N = 96):
- Sensitivity: 100% (95% Confidence Limits: 85.9% - 100%)
- Specificity: 100% (95% Confidence Limits: 93.1% - 100%)
Reproducibility (N=8 fecal specimens; 2 negative, 2 high negative, 2 low positive, 2 moderate positive):
- Tested at 2 independent laboratories and on-site at TECHLAB, Inc.
- Samples tested in triplicate, twice a day over a 5-day period by multiple technicians using 2 different kit lots.
- Results were consistent among different locations, exhibiting 100% correlation.
- Samples produced expected results 100% of the time.
Analytical Sensitivity (Limit of Detection - LoD):
- LoD for E. histolytica: 320 PZs/mL (equivalent to 15 PZs detected per test).
- For specimens in Cary Blair media: 275 PZs/mL (equivalent to 14 PZs detected per test).
- For specimens in C&S media: 245 PZs/mL (equivalent to 12 PZs detected per test).
- Determined following CLSI document EP17-A2. LoD defined as concentration yielding 95% positive results and 5% negative results.
Analytical Specificity (Cross Reactivity):
- No interference found with 21 bacterial and viral strains listed (e.g., Aeromonas hydrophila, Bacillus cereus, Campylobacter jejuni, E.coli, Salmonella typhimurium, Shigella species, Staphylococcus aureus, Yersinia enterocolitica).
- No cross reactivity found with 50 Norovirus GI/GII clinical specimens.
- No cross-reactivity seen with 8 other parasites documented by microscopy (e.g., Ascaris lumbricoides, Giardia spp., Cryptosporidium spp., Entamoeba coli).
- Strain specific study showed E. histolytica results positive from 244 to 30.5 pathogenic zymodemes (PZs)/mL.
- E. dispar results were negative at all dilutions beginning at 2440 non-pathogenic zymodemes (NPZs)/mL, demonstrating no cross-reactivity with E. dispar.
- 3 specimens positive for Entamoeba moshkovskii and 3 for Entamoeba bangladeshi tested negative with the subject device.
Interfering Substances (U.S. Formulation):
- No effect on positive or negative test results observed with various substances at specified concentrations (e.g., Barium sulfate, Benzalkonium Chloride, Ciprofloxacin, Ethanol, Human blood, Imodium®, Kaopectate®, Maalox®, Mineral Oil, Mylanta®, Naproxen Sodium, Pepto-Bismol®, Polyethylene glycol 3350, Simethicone, Human Urine, Vancomycin).
Precision:
- Intra-assay: 12 human fecal specimens (6 positive, 6 negative for E. histolytica) assayed five times in the same test run using two different kit lots. All positive samples remained positive and all negative samples remained negative. Overall correlation was 100%.
- Inter-assay: 8 human fecal specimens (2 negative, 2 high negative, 2 low positive, 2 moderate positive) tested twice a day by multiple technicians over a 12-day period using 2 different kit lots. All positive samples remained positive and all negative samples remained negative.
Prozone:
- No overall prozone effect observed; elevated levels of E. histolytica antigen did not affect antigen detection.
Fresh versus Frozen Samples:
- 15 fecal specimens (negative, high negative, low positive, moderate positive, high positive) stored at ≤ -10°C for 0, 1, 4, 8, 12, 16, 20, 24, and 28 weeks.
- No conversion of positive-to-negative or negative-to-positive was observed at any specified time points.
Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)
Prospective Clinical Performance:
Sensitivity: 40.0%
Specificity: 100%
Predictive Positive Value: 100%
Predictive Negative Value: 99.6%
Retrospective Clinical Performance:
Sensitivity: 100%
Specificity: 100%
Reproducibility: 100% correlation, 100% expected results.
Analytical Sensitivity (LoD):
320 PZs/mL for E. histolytica (equivalent to 15 PZs detected per test).
275 PZs/mL for E. histolytica in Cary Blair media (equivalent to 14 PZs detected per test).
245 PZs/mL for E. histolytica in C&S media (equivalent to 12 PZs detected per test).
Predicate Device(s): If the device was cleared using the 510(k) pathway, identify the Predicate Device(s) K/DEN number used to claim substantial equivalence and list them here in a comma separated list exactly as they appear in the text. List the primary predicate first in the list.
Reference Device(s): Identify the Reference Device(s) K/DEN number and list them here in a comma separated list exactly as they appear in the text.
Not Found
Predetermined Change Control Plan (PCCP) - All Relevant Information for the subject device only (e.g. presence / absence, what scope was granted / cleared under the PCCP, any restrictions, etc).
Not Found
§ 866.3220
Entamoeba histolytica serological reagents.(a)
Identification. Entamoeba histolytica serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies toEntamoeba histolytica in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identifyEntamoeba histolytica directly from clinical specimens. The identification aids in the diagnosis of amebiasis caused by the microscopic protozoan parasiteEntamoeba histolytica and provides epidemiological information on diseases caused by this parasite. The parasite may invade the skin, liver, intestines, lungs, and diaphragm, causing disease conditions such as indolent ulcers, an amebic hepatitis, amebic dysentery, and pulmonary lesions.(b)
Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.
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Image /page/0/Picture/1 description: The image shows the seal of the Department of Health & Human Services - USA. The seal is circular, with the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged around the perimeter. In the center of the seal is a stylized image of three human profiles facing to the right. The profiles are stacked on top of each other, with the top profile being the largest and the bottom profile being the smallest.
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
June 7, 2017
TECHLAB, INC. DONNA LINK DIRECTOR REGULATORY AND COMPLIANCE 2001 KRAFT DRIVE BLACKSBURG VA 24060-6358
Re: K170728
Trade/Device Name: E. Histolytica Ouik Chek Regulation Number: 21 CFR 866.3220 Regulation Name: Entamoeba histolytica serological reagents Regulatory Class: II Product Code: KHW Dated: March 8, 2017 Received: March 9, 2017
Dear Ms. Link:
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.
1
If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education 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. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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 Industry and Consumer Education 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.
Sincerely yours,
Ribhi Shawar -S For
Uwe Schef, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health
Enclosure
2
Indications for Use
510(k) Number (if known) K170728
Device Name E. HISTOLYTICA QUIK CHEKTM
Indications for Use (Describe)
The TECHLAB E. HISTOLYTICA QUIK CHEK™ test is a rapid membrane enzyme immunoassay for the qualitative detection of adhesin from Entamoeba histolytica in a single use cassette. It is intended for use with human fecal specimens from patients with diarrhea or dysentery as an aid in the diagnosis of E. histolytica gastrointestinal infection. Test results should be considered in conjunction with patient history.
FOR IN VITRO DIAGNOSTIC USE
| Type of Use (Select one or both, as applicable) | |
|---|---|
| ✖ Prescription Use (Part 21 CFR 801 Subpart D) | ☐ Over-The-Counter Use (21 CFR 801 Subpart C) |
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3
E. HISTOLYTICA QUIK CHEK™ 510(k) SUMMARY
This summary of 510(k) safety and effectiveness is being submitted in accordance with the requirements of 21 CFR 807.92.
Applicant/Contact Information:
| Date Prepared: | June 1, 2017 |
|---|---|
| Name: | TECHLAB, Inc. |
| Address: | 2001 Kraft Drive |
| Corporate Research Center | |
| Blacksburg, VA 24060 USA |
| Contact Person: | Donna T. Link |
|---|---|
| Phone Number: | 540-953-1664 |
| Email: | dlink@techlab.com |
1.1 Manufacturing Facility Address
TECHLAB, Inc. 20 Corporate Drive Radford, VA 24141 USA
1.2 Product and Trade Name of the Device
E. HISTOLYTICA QUIK CHEK™
1.3 Common Name or Classification Name
E. histolytica detection test
1.4 Classification and Regulation
21 CFR 866.3220; Entamoeba histolytica serological reagents
1.5 Product Code
KHW - Antigen, Id, Ha, Cep, Entamoeba histolytica & Rel. Spp.
1.6 Panel
83 Microbiology
Class II
4
Intended Use
The TECHLAB® E. HISTOLYTICA QUIK CHEK™ test is a rapid membrane enzyme immunoassay for the qualitative detection of adhesin from Entamoeba histolytica in a single use cassette. It is intended for use with human fecal specimens from patients with diarrhea or dysentery as an aid in the diagnosis of E. histolytica gastrointestinal infection. Test results should be considered in coniunction with patient history.
FOR IN VITRO DIAGNOSTIC USE
Explanation
Entamoeba histolytica and Entamoeba dispar are intestinal parasites that infect approximately half a billion people worldwide each year. It is necessary to distinguish between the two species because E. histolytica is pathogenic, causing intestinal amebiasis (e.g. diarrhea. dysentery, colitis) and extra-intestinal amebiasis (e.q. liver abscess). E. dispar is not associated with symptomatic disease and inaccurate diagnosis may result in unnecessary treatment. The most common method used to diagnose amebiasis has been wet mount microscopy, which suffers from poor sensitivity and specificity. Trophozoites and cysts are not easily identified in a single fecal specimen and it is difficult to visually distinguish between E. dispar and E. histolytica when they are observed. Detection of Entamoeba spp. by immunoassay provides an alternative method of diagnosis with greater sensitivity. Immunoassays specific for E. histolytica, such as the E. HISTOL YTICA QUIK CHEK™ test, provide the added benefit of only identifying E. histolytica infections. Large numbers of specimens can be tested rapidly and objectively, and the procedure is less labor-intensive than most other methods of diagnosis.
Device Description
The E. HISTOLYTICA QUIK CHEK™ test uses antibodies to adhesin. The device contains a Reaction Window with two vertical lines of immobilized antibodies. The test line ("T") contains monoclonal antibodies specific for E. histolytica adhesin. The control line ("C") contains antibodies to horseradish peroxidase (HRP). The Conjugate consists of polyclonal antibodies to E. histolytica adhesin coupled to horseradish peroxidase. To perform the test, the sample is added to a tube containing a mixture of Diluent and Conjugate. The diluted sample-conjugate mixture is added to the Sample Well and the device is allowed to incubate at room temperature for 15 minutes. During the incubation, E. histolytica adhesin in the samples bind to the antibodyperoxidase conjugate. The antigen-antibody complexes migrate through a filter pad to a membrane where they are captured by the immobilized antibodies in the Reaction Window is subsequently washed with Wash Buffer, and the test is developed with the addition of Substrate. After a 10 minute incubation period, the "T" reaction is examined visually for the appearance of a vertical blue line on the "T" side of the Reaction Window. A blue line indicates a positive test. A positive "C" reaction, indicated by a vertical blue line on the "C" side of the Reaction Window, monitors/confirms that the sample and reagents were added correctly, the reagents were active at the time of performing the assay, and that the sample migrated properly through the Membrane Device. It also confirms the reactivity of the other reagents associated with the assay.
Materials Provided
- . Diluent (16 mL) - Buffered protein solution with graduated dropper assembly
- Positive Control (1 mL) E. histolytica antigen in a buffered protein solution .
5
- Membrane Devices 25 pouches, each containing 1 device ●
- . Wash Buffer (12 mL) – Buffered solution with graduated dropper assembly
- . Substrate (3.5 mL) - Solution containing tetramethylbenzidine
- Conjugate (2 mL) Antibody specific for E. histolytica coupled to horseradish . peroxidase in a buffered protein solution
- . Disposable plastic pipettes - graduated at 25 µL, 100 µL, 200 µL, 300 µL, 400 µL and 500 ml
The predicate device (E. HISTOLYTICA I/™) and the E. HISTOLYTICA QUIK CHEK™ test use the same EIA (enzyme immunoassay) technology and are substantially equivalent in principle. The following tables show a comparison of both devices similarities and differences.
| Predicate Device Comparison Table
| Similarities | ||
|---|---|---|
| Item | E. HISTOLYTICA II TM | |
| (K994101) | E. HISTOLYTICA QUIK CHEK TM | |
| (K170028) | ||
| Intended Use | The E. HISTOLYTICA II TM is an enzyme | |
| immunoassay for the rapid detection of | ||
| the adhesin of E. histolytica in human | ||
| fecal specimens. It is indicated for use | ||
| with fecal specimens from patients with | ||
| diarrhea or dysentery to determine the | ||
| presence of E. histolytica gastrointestinal | ||
| infection. The test can be used for fecal | ||
| specimens submitted for routine clinical | ||
| testing from adults or children. | ||
| Conventional microscopy is not a | ||
| prerequisite for use of the test. | The TECHLAB® E. HISTOLYTICA QUIK CHEK TM test is a rapid membrane enzyme | |
| immunoassay for the qualitative detection | ||
| of adhesin from Entamoeba histolytica in a | ||
| single use cassette. It is intended for use | ||
| with human fecal specimens from patients | ||
| with diarrhea or dysentery as an aid in the | ||
| diagnosis of E. histolytica gastrointestinal | ||
| infection. Test results should be | ||
| considered in conjunction with patient | ||
| history. | ||
| Measured | ||
| analyte | E. histolytica specific antigen | E. histolytica specific antigen |
| Target | ||
| Population | Persons suspected of having | |
| E. histolytica infection | Persons suspected of having | |
| E. histolytica infection | ||
| Technology | Enzyme Linked Immunoassay (ELISA) | Enzyme Linked Immunoassay (ELISA) |
| Antibody Format | Monoclonal/Polyclonal | Monoclonal/Polyclonal |
| Type of Test | Qualitative | Qualitative |
| Sample Matrix | Human Fecal Specimen | Human Fecal Specimen |
| Controls | Positive and negative control included in | |
| the kit | Positive and negative control included in | |
| the kit | ||
| Storage | Refrigerated (2°C – 8°C) | Refrigerated (2°C – 8°C) |
6
| Predicate Device Comparison Table
| Differences | ||
|---|---|---|
| Item | E. HISTOLYTICA II TM | |
| (K994101) | E. HISTOLYTICA QUIK CHEK TM | |
| (K170028) | ||
| Format | 96 Well Microassay Plate | |
| 96 tests | Single Use Membrane Cassette | |
| 25 tests | ||
| Specimen Type | Cannot use Transport Media | Fecal specimens in Cary-Blair and C&S |
| Transport Media | ||
| Time to Result | Approximately 2.5 hours | 30 minutes |
| Controls | No internal control | Internal "C" Control line |
| Interpretation of Result | Spectrophotometric and Visual | Visual |
Comparative Information - Predicate Device (continued)
Summary of Performance Data
The performance of the E. HISTOL YTICA QUIK CHEK™ test was evaluated at 3 independent sites. A summary of overall performance at the 3 sites follows.
The performance of the E. HISTOLYTICA QUIK CHEK™ test was compared to the Composite Reference Method (CRM) as described below and included 755 fresh prospective and 96 frozen (retrospective) specimens.
The Composite Reference Method (CRM) results will be determined as follows:
| Microscopy | FDA cleared
multiplex NAAT test | Alternate PCR with
sequencing | CRM Result |
|------------|------------------------------------|----------------------------------|------------|
| Pos | Pos | Pos | Pos |
| Pos | Pos | Neg | Neg |
| Pos | Neg | Pos | Pos |
| Pos | Neg | Neg | Neg |
| Neg | Pos | Pos | Pos |
| Neg | Pos | Neg | Neg |
| Neg | Neg | N/A | Neg |
For the CRM result with Microscopy negative and FDA cleared multiplex NAAT test negative, no further testing was required.
7
A total of 851 fecal samples were evaluated and included 96 retrospective samples. Age information was available for 851 patients. Of the 851 patients. 18.9% were ≤ 20 years. Sex information was available for 851 patients, and 42.7% were male and 57.3% were female. Table 1 and 2 show a summary of the clinical performance of the E. HISTOLYTICA QUIK CHEK™ test. Table 1 represents the results for the prospective samples, of the 755 prospectively collected samples, 100 of the prospectively collected samples were diluted in Protocol™ Cary-Blair and Para-Pak® C&S, All of the samples diluted in transport media and tested were negative. The prospective testing did show that the E. HISTOLYTICA QUIK CHEK™ test exhibited a sensitivity of 40.0%, with a specificity of 100%, a predictive positive value of 100%, and a predictive negative value of 99.6% with the CRM. Table 2 represents the results for the retrospective samples, which showed that the E. HISTOLYTICA QUIK CHEK™ test exhibited a sensitivity and specificity of 100% with the CRM
Table 1. Summary of prospective clinical performance comparing the E. HISTOLYTICA QUIK CHEK™ test to the Composite Reference Method (CRM) Prospective Samples
| N = 755 | Composite Reference Method Positive | Composite Reference Method Negative |
|---|---|---|
| E. HISTOLYTICA QUIK CHEKTM | ||
| Positive | 2 | 0 |
| E. HISTOLYTICA QUIK CHEKTM | ||
| Negative | 3 | 750 |
| 95% Confidence Limits | ||
|---|---|---|
| Sensitivity | 40.0% | 7.3% - 83.0% |
| Specificity | 100% | 99.4% - 100% |
| Predictive Positive Value | 100% | 19.8% - 100% |
| Predictive Negative Value | 99.6% | 98.7% - 99.9% |
All three of the false negative results were PCR positive and antigen negative. Additional antigen testing was done with a previously cleared FDA device.
Table 2. Summary of retrospective clinical performance comparing the E. HISTOLYTICA QUIK CHEK™ test to the Composite Reference Method (CRM) Retrospective Samples
| N = 96 | Composite Reference Method
Positive | Composite Reference Method
Negative |
|----------------------------------------------|----------------------------------------|----------------------------------------|
| E. HISTOLYTICA QUIK CHEK™
Positive | 30 | 0 |
| E. HISTOLYTICA QUIK CHEK™
Negative | 0 | 66 |
| 95% Confidence Limits | ||
|---|---|---|
| Sensitivity | 100% | 85.9% - 100% |
| Specificity | 100% | 93.1% - 100% |
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Reproducibility
The reproducibility of the E. HISTOLYTICA QUIK CHEK™ test was determined using 8 fecal specimens that were coded to prevent their identification during testing. Testing was performed at 2 independent laboratories and on-site at TECHLAB. Inc. The samples included 2 negative samples, 2 high negative samples, 2 low positive samples and 2 moderate positive samples. The samples were tested in triplicate twice a day over a 5-day period by multiple technicians at each site using 2 different kit lots. A positive and negative control was run with each panel of the masked samples. The results from each laboratory were submitted to TECHLAB, Inc. and compared with in-house results were consistent among the different locations, and exhibited a correlation of 100%. The samples produced the expected results 100% of the time.
Analytical Sensitivity
The Limit of Detection for the E. HISTOLYTICA QUIK CHEK™ test was found to be 320 PZs/mL for E. histolytica (equivalent to 15 PZs detected per test). For specimens in Cary Blair media. the data supports analytical sensitivity claims of 275 PZs/mL for E. histolytica (equivalent to 14 PZs detected per test). For specimens in C&S media, the data supports analytical sensitivity claims of 245 PZs/mL for E. histolytica (equivalent to 12 PZs detected per test).
Limit of Detection (LoD) – cutoff points for E. histolytica pathogenic zymodemes in fecal specimens for the E. HISTOLYTICA QUIK CHEK™ test.
The LoD was determined following CLSI document EP17-A2. Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures; Approved Guideline-Second Edition.
The limit of detection of the E. HISTOLYTICA QUIK CHEK™ test was determined by using E. histolytica pathogenic zymodemes. The sensitivity of the E. HISTOLYTICA QUIK CHEK™ test for the detection of E. histolytica was determined using purified pathogenic zymodemes in a sample matrix.
The Limit of Detection (LoD) of the E. HISTOLYTICA QUIK CHEK™ test for E. histolytica, as determined with pathogenic zymodemes (PZs), was defined as the concentration of PZs which yielded positive results 95% of the time, and negative results 5% of the time. The analytical sensitivity was determined empirically by testing dilutions of pathogenic zymodemes (PZs) in a negative fecal sample matrix, in replicates of 20. Additionally, LoD was determined for E. histolytica pathogenic zymodemes in a negative fecal matrix/Cary Blair and negative fecal matrix/C&S media.
In conclusion, the data qenerated for Determination of Limitation of Detection (LOD), support Package Insert claims of Limit of Detection for the E. HISTOLYTICA QUIK CHEK™ test as 320 PZs/mL for E. histolytica (equivalent to 15 PZs detected per test). For specimens in Cary Blair media, the data supports analytical sensitivity claims of 275 PZs/mL for E. histolytica (equivalent to 14 PZs detected per test). For specimens in C&S media, the data supports analytical sensitivity claims of 245 PZs/mL for E. histolytica (equivalent to 12 PZs detected per test).
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Analytical Specificity (Cross Reactivity)
The E. HISTOLYTICA QUIK CHEK™ test was evaluated for cross-reactivity with the bacterial and viral strains listed below. None of the strains were shown to interfere with the performance E. HISTOLYTICA QUIK CHEK™ test.
| Aeromonas hydrophila | Bacillus cereus | Bacillus subtilis |
|---|---|---|
| Bacteroides fragilis | Campylobacter coli | Campylobacter fetus |
| Campylobacter jejuni | Candida albicans | Clostridium bifermentans |
| Clostridium difficile | Enterococcus faecalis | Escherichia coli |
| Escherichia coli 0157:H7 | Escherichia coli EIEC | Escherichia coli EPEC |
| Escherichia coli ETEC | Klebsiella pneumonia | Salmonella typhimurium |
| Shigella dysenteriae | Shigella flexneri | Shigella sonnei |
| Staphylococcus aureus | Staphylococcus aureus (Cowan's) | Staphylococcus epidermidis |
| Vibrio parahaemolyticus | Yersinia enterocolitica |
Cross reactivity with Norovirus is unknown because it was not tested in analytical studies. However, Norovirus GI/GII was identified in 50 clinical specimens using an FDA cleared multiplex NAAT assay during clinical testing and no cross reactivity was found using the E. HISTOLYTICA QUIK CHEK™ in those samples.
Additionally, the E. HISTOLYTICA QUIK CHEK™ test was run on fecal specimens documented to be positive for other parasites by microscopy. The number in parenthesis is the number of clinical specimens in which each organism was identified. No cross-reactivity was seen with the following organisms.
| Ascaris lumbricoides and with eggs (21) | Entamoeba bangladeshi (3) | Giardia spp. (45) |
|---|---|---|
| Blastocystis hominis (12) | Entamoeba coli (13) | Iodamoeba bütschlii (10) |
| Cryptosporidium spp. (30) | Entamoeba moshkovskii (3) | Trichuris trichiura eggs (11) |
Strain Specific Study
The specificity of the E. HISTOLYTICA QUIK CHEK™ test was also evaluated by examining the reactivity of pathogenic (Entamoeba histolytica) and non-pathogenic (Entamoeba dispar) zymodemes (strains) for reactivity by standard curve dilutions. E. histolytica results were positive from 244 to 30.5 pathogenic zymodemes (PZs)/mL and the E. dispar results were neqative at all dilutions beginning at 2440 non-pathogenic zymodemes (NPZs)/mL. The E. HISTOLYTICA QUIK CHEK™ test demonstrates proper reactivity with Entamoeba histolytica and does not cross-react with Entamoeba dispar.
Additionally, due to the similarity in morphology, 3 specimens identified by PCR as positive for Entamoeba moshkovskii and 3 postive for Entamoeba bangladeshi were evaluated using the E. HISTOLYTICA QUIK CHEK™ test. These 6 specimens all tested negative in the E. HISTOLYTICA QUIK CHEK™ test.
Interfering Substances (U.S. Formulation)
The following substances had no effect on positive or negative test results analyzed at the concentrations indicated:
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Barium sulfate (5% w/v), Benzalkonium Chloride (1% w/v), Ciprofloxacin (0.25% w/v), Ethanol (1% w/v), Hog gastric mucin (3.5% w/v), Human blood (40% v/v), Hydrocortisone (1% w/v), lmodium® (5% v/v), Kaopectate® (5% v/v), Leukocytes (0.05% w/v), Maalox® Advanced (5% v/v). Mesalazine (10% w/v). Metronidazole (0.25% w/v). Mineral Oil (10% w/v). Mylanta® (4.2 mg/mL), Naproxen Sodium (5% w/v), Nonoxynol-9 (40% w/v), Nystatin (1% w/v), Palmitic Acid/Fecal Fat (40% w/v), Pepto-Bismol® (5% v/v), Phenylephrine (1% w/v), Polyethylene glycol 3350 (10% w/v ), Priolsec OTC® (5 µg/mL), Sennosides (1% w/v), Simethicone (10% w/v), Steric Acid/Fecal Fat (40% w/v), Tagamet® (5 µg/mL), TUMS (50 µg/mL), Human Urine (5% v/v), and Vancomycin (0.25% w/v).
Precision - Intra-assay
For the determination of intra-assay performance, twelve human fecal specimens were analyzed by the E. HISTOLYTICA QUIK CHEK™ test. Of these twelve specimens, six were positive for E. histolytica of varying levels (low, moderate, and high) and six were negative for E. histolytica. Each specimen was assayed five times in the same test run, using two different kit lots. A positive and negative control was run with each panel. All positive samples remained positive and all negative samples remained negative. The overall correlation between the results was 100%.
Precision - Inter-assay
For the determination of inter-assay performance, eight human fecal specimens were analyzed by the E. HISTOLYTICA QUIK CHEK test. The samples included 2 negative samples, 2 high negative samples, 2 low positive samples and 2 moderate positive samples. The samples were tested, twice a day by multiple technicians over a 12-day period using 2 different kit lots. A positive and negative control was run on each day. All positive samples remained positive and all negative samples remained negative.
Prozone
To ensure that a high concentration of E. histolytica antigen does not interfere with a positive reaction in the E. HISTOLYTICA QUIK CHEK™ test, high samples were prepared by spiking a negative fecal pool at a concentration possibly observed in clinical specimens. A total of 5 different dilutions of the antigen, up to and including the clinically observed high concentration, were prepared and tested in triplicate. The results demonstrated that there was no overall prozone affect, that elevated levels of antigen did not affect the detection of the antigen.
Fresh versus Frozen Samples
The effect of long term frozen specimen storage on antigen stability was evaluated. For the analysis, a total of 15 fecal specimens were tested with the E. HISTOLYTICA QUIK CHEK™ test. The fecal specimens consisted of 3 negative fecal samples, 3 E. histolytica high negative fecal samples, 3 E. histolytica low positive fecal samples, 3 E. histolytica moderate positive fecal samples, and 3 E. histolytica high positive fecal samples. Samples were prepared and stored ≤ -10°C at 0. 1. and 4. 8. 12. 16. 20. 24 and 28 weeks. No conversion of positive-to-negative or negative-to-positive was observed in any of the samples at the specified time points.
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Conclusion
The conclusions drawn from the nonclinical and clinical tests demonstrate that the E. HISTOLYTICA QUIK CHEK™ test is as safe and as effective and performs as well or better than the predicate devices and composite reference method used in the evaluations. The information submitted in this premarket notification is complete and supports a substantial equivalence decision.