(15 days)
The E. histolytica II 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 routine prerequisite for use of the test. FOR IN VITRO DIAGNOSTIC USE.
The E. histolytica II can be used to detect adhesin (also referred to as galactose-inhibitable lectin) produced by strains of E. histolytica. It does not cross-react with the adhesin from E. dispar (formerly known as nonpathogenic E. histolytica). The test can be used to detect the adhesin in fecal specimens from persons suspected of having amebiasis. The kit, which includes ready-to-use reagents, contains microtiter wells coated with polyclonal antibody, positive control reagent, monoclonal-antibody conjugate, diluent, one component substrate, wash solution, and stop solution. The microtiter wells coated with polyclonal antibody "capture" the adhesin and the monoclonal antibody conjugate serves as the "detecting" antibody. The polyclonal antibody used to coat the wells is prepared from hyperimmune antiserum developed in goats. The monoclonal antibody used to prepare the conjugate is prepared from mouse ascites fluid. The E. histolytica II is to be used in an ELISA format.
Here's an analysis of the acceptance criteria and the study proving the device's performance, based on the provided text:
Device Name: E. histolytica II
1. Table of Acceptance Criteria and Reported Device Performance:
The document explicitly states that "No performance standards have been developed for this device under §514 of the Food, Drug, and Cosmetic Act." Therefore, formal acceptance criteria in terms of specific sensitivity, specificity, or accuracy thresholds are not listed. Instead, the study's goal was to demonstrate substantial equivalence and improved sensitivity compared to a predicate device and a "gold standard."
The reported performance focuses on correlation with the gold standard and improved sensitivity compared to a previous test.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| > Substantial equivalence to culturing and zymodeme analysis | > "substantially equivalent to culturing and zymodeme analysis" |
| > More sensitive than predicate device (E. histolytica TEST) | > "more sensitive than our E. histolytica TEST" |
| > High specificity for pathogenic E. histolytica | > "highly specific for pathogenic Entamoeba" |
| > Correlation with zymodeme analysis | > "correlation of >97% when compared with zymodeme analysis" |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size for Test Set: The exact number of stool specimens analyzed in the clinical evaluations is not specified in the provided text. It only states that the E. histolytica II was used to analyze "stool specimens in areas where amebiasis is endemic."
- Data Provenance:
- Country of Origin: Not explicitly stated, but the phrase "areas where amebiasis is endemic" suggests diverse geographical locations where the disease is prevalent.
- Retrospective or Prospective: Not explicitly stated. The description "the E. histolytica II was used to analyze stool specimens...and the results were compared with zymodeme analysis...and with the E. histolytica TEST" could imply either retrospective analysis of archived samples or prospective collection. Without further detail, it cannot be definitively determined.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- Number of Experts: Not specified.
- Qualifications of Experts: Not specified. The "zymodeme analysis" is described as being performed in "a select number of clinical laboratories around the world" that are "capable of performing this type of analysis." This implies highly specialized personnel, but specific qualifications are not detailed.
4. Adjudication Method for the Test Set:
- The text does not describe an explicit adjudication method between multiple readers or experts for the test set. The ground truth ("gold standard") was established by "zymodeme analysis." The E. histolytica II results were then compared to this established ground truth, rather than adjudicated by experts confirming the E. histolytica II results.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done:
- No, an MRMC comparative effectiveness study involving human readers and AI assistance was not performed. This device is an in-vitro diagnostic (IVD) ELISA kit, not an AI or imaging-based device that would typically involve human readers interpreting results with or without AI assistance. The comparisons are between different diagnostic tests (ELISA kit vs. culture/zymodeme vs. predicate ELISA kit).
6. If a Standalone Study (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, in spirit, a standalone study was performed. The E. histolytica II kit itself is a standalone diagnostic tool. Its performance (detecting adhesin) was evaluated and compared directly against a "gold standard" (zymodeme analysis) and a predicate device (E. histolytica TEST) without human interpretation steps that would fundamentally alter the E. histolytica II's core measurement. The kit provides a direct result (e.g., color change indicating presence of adhesin).
7. The Type of Ground Truth Used:
- Expert Consensus / Gold Standard: The ground truth used was zymodeme analysis. The document explicitly states, "For the purpose of our studies, zymodeme analysis represents the 'gold standard'." Zymodeme analysis determines if an isolated Entamoeba strain is pathogenic, which is the specific target of the E. histolytica II.
8. The Sample Size for the Training Set:
- Not applicable / Not specified. As this is a traditional ELISA kit rather than a machine learning model, there isn't a "training set" in the conventional AI sense. The development of the antibodies and optimization of the assay would have involved various experimental samples, but these are not referred to as a "training set" in the context of AI.
9. How the Ground Truth for the Training Set was Established:
- Not applicable / Not specified. For an ELISA kit, the "ground truth" for developing the kit involves standard laboratory practices for antigen/antibody characterization, cross-reactivity testing, and determining optimal assay conditions. This would involve known positive and negative samples, purified antigens, and characterized strains, but it's not described as a "training set" with established ground truth in the same way as an AI model. The document mainly describes the components of the kit and its mechanism of action.
§ 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.