The Chlamydia IgG ELISA kit is an Enzyme-Linked Immunosorbent Assay (ELISA) for qualitative detection of IgG antibodies in human serum to Chlamydia for the determination of immunological experience.

Device Description

The Chlamydia IgG ELISA test is an enzyme linked immunosorbent assay to detect IgG antibodies to Chlamydia. Purified Chlamydia antigen (strain LGV II) is attached to a solid phase microtiter well. Diluted test sera is added to each well. If the antibodies are present that recognize the antigen, they will bind to the antigen in the well. After incubation the wells are washed to remove unbound antibody. An enzyme labeled anti-human IgG is added to each well. If antibody is present it will bind to the antibody attached to the antigen on the well. After incubation the wells are washed to remove unbound conjugate. A substrate solution is added to each well. If enzyme is present the substrate will undergo a color change. After an incubation period the reaction is stopped and the color intensity is measured photometrically, producing an indirect measurement of specific antibody in the patient specimen.

AI/ML Overview

Here's an analysis of the acceptance criteria and study detailed in the provided text, formatted as requested:

Acceptance Criteria and Device Performance for Chlamydia IgG ELISA Test Kit

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria	Reported Device Performance (Chlamydia IgG ELISA)
Relative Sensitivity	92.1% (95% CI: 86.3% - 97.8%)
Relative Specificity	98.0% (95% CI: 96.2% - 99.8%)
Relative Agreement	96.5% (95% CI: 94.5% - 98.5%)
Precision (CV)	Intra-assay CV: typically <15% (e.g., 2.57% to 19.95% in Study 1, 1.69% to 53.59% in Study 2). Inter-assay CV: 3.41% to 17.75%. Inter-site CV: 4.63% to 78.91%
Reproducibility (% Agreement between sites)	97.1% (excluding equivocals)
Seroconversion Detection (Sensitivity vs. CF titer)	44% (4/9) for demonstrating seroconversion

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

Sample Size: 355 sera were used for the relative sensitivity and specificity analysis.
Data Provenance: The sera were from "normal individuals of various ages, gender, and geographical areas." The study was conducted at "R&D laboratories at commercial companies located in Maryland and New York and affiliated with the manufacturing of the kit." This indicates a prospective and likely geographically diverse dataset, but specifically not from patients with documented Chlamydia infections.

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

Not applicable. The ground truth for the relative sensitivity and specificity study was established by a predicate device (commercial IFA kit), not by human experts interpreting images or clinical data.

4. Adjudication Method for the Test Set

Not applicable. The performance was compared against a predicate device, not against a consensus of human reviewers. Equivocal results from the comparison were excluded from the calculations of sensitivity, specificity, and agreement.

5. 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

Not applicable. This is a diagnostic immunoassay kit, not an AI-assisted diagnostic tool for human readers.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

Yes, the studies on relative sensitivity, specificity, and precision assess the standalone performance of the Chlamydia IgG ELISA test kit. There is no human interpretation component in the ELISA assay itself once the sample is processed.

7. The Type of Ground Truth Used

The ground truth for the relative sensitivity and specificity study was defined by the results of a commercial IFA kit (Immunofluorescence Assay). The document explicitly states: "Please be advised that 'relative' refers to the comparison of this assay's results to that of a similar assay. There was not an attempt to correlate the assay's results with disease presence or absence. No judgment can be made on the comparison assay's accuracy to predict disease."
For the seroconversion study, the ground truth was a "greater than 4 fold increase in CF titer or seroconversions by CF" as determined by a Complement Fixation (CF) assay.

8. The Sample Size for the Training Set

Not applicable. This is a non-AI diagnostic kit; there is no "training set" in the context of machine learning. The "training" would be the process of developing and optimizing the assay itself, which is not detailed in terms of a specific sample size.

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

Not applicable, as explained in point 8.

Summary

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K962558

Summary of Safety and Effectiveness Information Chlamydia IgG ELISA Test Kit

FEB 2 4 1997

I. Immuno Probe Inc. 1306 Bailes Lane, Suite F Frederick, Maryland 21701 Contact person: William Boteler Telephone: 301-695-7920 Date of preparation: Jan 13, 1996

II. Description of Device

The Chlamydia IgG ELISA kit is an Enzyme-Linked Immunosorbent Assay (ELISA) for qualitative detection of IgG antibodies in human serum to Chlamydia for the determination of immunological experience.

III. Predicate Device

The Chlamydia IgG ELISA test is substantially equivalent to IFA. Equivalence is demonstrated by the following comparative results:

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Performance Characteristics

Relative sensitivity and specificity. Two different sites compared the Wampole Chlamydia IgG ELISA test relative to a commercial IFA kit. The two sites were R&D laboratories at commercial companies located in Maryland and New York and affiliated with the manufacturing of the kit. The sera were from normal individuals of various ages, gender, and geographical areas. The results of the studies are compiled and summarized in Table 1. None of the performance characteristics were established with specimens from patients having documented chlamydia infections.

Table 1 Comparison of Chiamydia IgG ELISA and IFA

		+	eq	-	Total
	+ >1:8	81	7	7	95
ChlamydiaIFA	- <1:8	5	9	246	260
	Total	86	16	253	355

Wampole Chlamydia IgG ELISA

Relative Sensitivity = 81/88 = 92.1%	95% Confidence interval = 86.3% - 97.8%
Relative Specificity = 246/251 = 98.0%	95% Confidence interval = 96.2% - 99.8%
Relative Agreement = 327/339 = 96.5%	95% Confidence interval = 94.5% - 98.5%

Equivocals were not included in the above calculations.

The 95% confidence intervals were calculated using the normal method.

Please be advised that 'relative' refers to the comparison of this assay's results to that of a similar assay. There was not an attempt to correlate the assay's results with disease presence or absence. No judgment can be made on the comparison assay's accuracy to predict disease.

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Precision. Seven sera were assayed ten times each on three different assays at two different sites. Both sites were affiliated with the manufacturing of the kit. The inter and intra assay precision for each site is presented in Tables 2 and 3 and the intersite precision is shown in Table 4. With appropriate technique the user should obtain precision of <15% CV.

Table 2 Chlamydia IgG ELISA Intra and Inter Assay Precision Study 1

Assay(n=30)	Assay 1 (n=10)			Assay 2 (n=10)			Assay 3 (n=10)			Inter-
Sera#	X	SD	CV	X	SD	CV	X	SD	CV	X	SD	CV
1	2.86	0.152	5.32%	2.97	0.076	2.57%	3.13	0.115	3.69%	2.99	0.162	5.42%
2	1.71	0.101	5.91%	1.88	0.098	5.20%	1.90	0.092	4.89%	1.83	0.129	7.05%
3	1.74	0.107	6.15%	1.87	0.071	3.78%	1.95	0.072	3.67%	1.85	0.121	6.50%
4	1.78	0.126	7.07%	1.92	0.053	2.77%	2.03	0.075	3.72%	1.91	0.135	7.06%
5	1.06	0.051	4.83%	1.12	0.034	3.00%	1.16	0.049	4.24%	1.11	0.060	5.42%
6	0.34	0.032	9.59%	0.32	0.042	13.06%	0.37	0.052	14.25%	0.34	0.046	13.55%
7	0.30	0.061	19.95%	0.29	0.056	19.43%	0.33	0.043	12.81%	0.31	0.054	17.75%

Table 3 Chlamydia IgG ELISA Intra and Inter Assay Precision Study 2

Sera#	Assay 1 (n=10)			Assay 2 (n=10)			Assay 3 (n=10)			Inter-Assay(n=30)
	X	SD	CV	X	SD	CV	X	SD	CV	X	SD	CV
1	3.08	0.052	1.69%	3.11	0.106	3.40%	3.00	0.117	3.91%	3.06	0.104	3.41%
2	1.77	0.085	4.80%	1.78	0.073	4.10%	1.75	0.094	5.38%	1.77	0.084	4.75%
3	1.86	0.062	3.35%	1.85	0.086	4.63%	1.86	0.083	4.46%	1.86	0.076	4.08%
4	1.81	0.060	3.30%	1.84	0.112	6.12%	1.84	0.102	5.52%	1.83	0.091	4.98%
5	0.93	0.051	5.46%	0.93	0.071	7.69%	0.94	0.053	5.61%	0.93	0.058	6.19%
6	0.04	0.014	31.17%	0.03	0.018	53.59%	0.06	0.024	39.50%	0.05	0.022	46.90%
7	0.05	0.016	35.60%	0.05	0.015	32.60%	0.07	0.032	47.62%	0.05	0.024	45.41%

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Table 4 Chlamydia IgG ELISA Inter Site Precision Study

Sera #	X	SD	CV
1.	3.03	0.140	4.63%
2.	1.80	0.112	6.24%
3.	1.86	0.100	5.37%
4.	1.87	0.121	6.46%
5.	1.02	0.110	10.73%
6.	0.19	0.153	78.91%
7	0.18	0.137	75.20%

Inter-Site (n=60)

X = Mean

SD = standard deviation

CV = coefficient of variation = SD/X x 100

Refer to NCCLS EP5 for guidance for appropriate precision determination.

CF Paired Serum Analysis. Nine serum pairs showing a greater than 4 fold increase in CF titer or seroconversions by CF were assayed on the Chlamydia IgG ELISA assay. Each serum pair was evaluated to determine an seroconversion in antibody (acute negative and convalescent positive). Four pairs demonstrated a seroconversion by ELISA. Therefore the assay showed a sensitivity of 44% (4/9) in demonstrating a seroconversion when the CF showed a 4 fold increase or a seroconversion.
Reproducibility Study. Fifty different sera with various levels of activity were assayed at three different sites. Two sites were R&D laboratories at commercial companies located in Maryland and New York. The third site was a large clinical laboratory located in Pennsylvania. The data from the three sites show good correlation with ISR values with product moment correlation coefficients of >0.989 between the sites. Excluding equivocals (n = 13) four determinations varied from its expected result (negative results for a positive specimen) giving a %agreement of expected results between the three sites of 97.1% (133/137). The expected results were derived from previous Wampole ELISA testing of the samples.

Regulation Number and Section

§ 866.3120 Chlamydia serological reagents.

(a)
Identification. Chlamydia serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to chlamydia in serum. Additionally, some of these reagents consist of chlamydia antisera conjugated with a fluorescent dye used to identify chlamydia directly from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of disease caused by bacteria belonging to the genusChlamydia and provides epidemiological information on these diseases. Chlamydia are the causative agents of psittacosis (a form of pneumonia), lymphogranuloma venereum (a venereal disease), and trachoma (a chronic disease of the eye and eyelid).(b)
Classification. Class I (general controls).