(192 days)
for the qualitative detection of total antibodies (IgG and IgM) 10 Legionella pneumophila serogroups 1-6 in serum from patients with clinical suspicion of Legionella Disease.
The Legionella pneumophila IgG/IgM ELISA kit is an Enzyme-Linked Immunosorbent Assay (ELISA) for the qualitative detection of total antibodies (IgG and IgM) 10 Legionella pneumophila serogroups 1-6 in serum from patients with clinical suspicion of Legionella Disease.
The Legionella pneumophila IgG/IgM ELISA test is an enzyme linked immunosorbent assay to detect IgG/IgM antibodies to Legionella. Purified Legionella pneumopilla antigen (serogroups 1, 2, 3, 4, 5, 6) 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/IgM 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.
Here's a breakdown of the acceptance criteria and study information for the Legionella pneumophila IgG/IgM ELISA Test Kit, based on the provided text:
1. Acceptance Criteria and Reported Device Performance
The provided document doesn't explicitly state numerical "acceptance criteria" in the typical sense (e.g., a pre-defined threshold that must be met for approval). Instead, it presents "Performance Characteristics" and compares the device's performance to a predicate device (BioWhitttaker's Legionella STAT test) and a reference method (IFA). The reported performance values are those observed in these comparative studies.
Table of Acceptance Criteria (Implied) and Reported Device Performance:
| Performance Metric | Implied Acceptance Criterion (from predicate comparison) | Reported Device Performance |
|---|---|---|
| Relative Sensitivity (Vs IFA) | Comparable to predicate or reference method | 90.00% (95% CI: 79.0% - 100%) |
| Relative Specificity (Vs IFA) | Comparable to predicate or reference method | 98.53% (95% CI: 95.6% - 100%) |
| Relative Agreement (Vs IFA) | Comparable to predicate or reference method | 98.57% (95% CI: 95.7% - 100%) |
| Seroconversion Sensitivity (CDC Panel) | Demonstrate ability to detect seroconversion | 93.5% (29/31 seroconversions detected) |
| Precision (Intra-assay CV) | Not explicitly stated, but generally <15-20% | Ranges from 2.72% to 15.5% (Site 1) and 5.00% to 11.4% (Site 2) |
| Precision (Inter-assay CV) | Not explicitly stated, but generally <15-20% | Ranges from 7.50% to 15.9% (Site 1) and 7.14% to 9.54% (Site 2) |
| Precision (Inter-site CV) | Not explicitly stated, but generally <20% | Ranges from 7.50% to 19.2% |
Note: The phrase "substantially equivalent to BioWhitttaker's Legionella STAT test" implies that the acceptance criteria are met if the performance characteristics are similar or non-inferior to the predicate device. The document does not provide specific numerical criteria for the predicate device.
2. Sample Sizes Used for the Test Set and Data Provenance
- Test Set 1 (Commercial R&D Lab - Maryland):
- Sample Size: 33 single IFA positive sera (from an outbreak and routine submissions).
- Data Provenance: United States (Maryland), Retrospective (samples routinely submitted or from an outbreak)
- Test Set 2 (Clinical Laboratory - Pennsylvania):
- Sample Size: 72 prospective serum samples for Legionella testing.
- Data Provenance: United States (Pennsylvania), Prospective
- CDC Panel (Seroconversion Study):
- Sample Size: 31 serum pairs (total 62 individual serum samples).
- Data Provenance: United States (CDC-confirmed panel), Retrospective (samples submitted to CDC for titer confirmation)
- Precision Studies (Various Sera):
- Sample Size:
- 7 different sera at two sites, tested 10 times each on 3 different days (7 sera x 2 sites x 30 tests/site = 420 tests).
- An additional 3 sera at Site 1, tested 10 times each on 3 different days (3 sera x 30 tests = 90 tests).
- Control samples (HPC, CAL, LPC, NC) also included.
- Data Provenance: Unspecified, likely United States (commercial R&D lab in Maryland and clinical lab in Pennsylvania).
- Sample Size:
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The ground truth for the primary comparative studies was established using Legionella IFA (Immunofluorescence Assay) results. This is a laboratory-based assay, not typically requiring human expert interpretation in the same way as imaging studies.
- The IFA results for the first test set were "Legionella positive sera from an outbreak and samples routinely submitted for Legionella testing."
- The IFA results for the second test set were "prospective serum for Legionella testing."
- For the CDC panel, the IFA titers were "confirmed to be serologically positive for an increase in titer from < 1:256 to >1:256."
The document does not explicitly state the number of human experts involved in interpreting the IFA results or their specific qualifications (e.g., medical technologists, clinical pathologists). However, IFA is a standardized laboratory test, and its results are generally considered objective.
4. Adjudication Method for the Test Set
The document does not describe an adjudication method in the context of human readers interpreting data. The comparisons are made against established laboratory test results (IFA). Equivocal results from the ELISA device were "not included in the above calculations" for sensitivity and specificity, which acts as a form of handling ambiguous results rather than human adjudication of ground truth.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not done. This study focuses on the performance of a diagnostic kit (ELISA) compared to another diagnostic kit (IFA), not on human reader performance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
Yes, the studies presented are standalone performance evaluations of the Legionella pneumophila IgG/IgM ELISA Test Kit. The results (Relative Sensitivity, Specificity, Agreement, Seroconversion Sensitivity, and Precision) reflect the performance of the assay itself, without any human-in-the-loop interaction influencing the calculation of these metrics.
7. The Type of Ground Truth Used
The primary ground truth used for performance evaluation was:
- Legionella IFA (Immunofluorescence Assay) results: This is a laboratory-based method for detecting Legionella antibodies and is used as the reference standard in the comparative studies.
- CDC-confirmed IFNA titer changes: For the seroconversion study, the ground truth was a confirmed greater than 4-fold increase in IFA titer from the CDC.
The document explicitly states: "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." This means the ground truth is based on a serological reference method, not clinical disease outcomes (e.g., pathology confirmation or patient follow-up).
8. The Sample Size for the Training Set
The document does not mention a training set or machine learning/AI development. This is a traditional in vitro diagnostic (IVD) device, and its performance is evaluated through clinical laboratory studies comparing it to established methods, rather than through a machine learning development pipeline involving training and test sets in the AI sense.
9. How the Ground Truth for the Training Set was Established
As there is no mention of a training set for an AI/ML algorithm, this question is not applicable to the provided document.
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Summary of Safety and Effectiveness Information Legionella pneumophila IgG/IgM ELISA Test Kit
MAR - 3 1997
I. Immuno Probe Inc. 1306 Bailes Lane, Suite F Frederick, Maryland 21701 Contact person: William Boteler Telephone: 301-695-7920 Date of preparation: Feb 13, 1997
II. Description of Device
The Legionella pneumophila IgG/IgM ELISA kit is an Enzyme-Linked Immunosorbent Assay (ELISA) for the qualitative detection of total antibodies (IgG and IgM) 10 Legionella pneumophila serogroups 1-6 in serum from patients with clinical suspicion of Legionella Disease.
The Legionella pneumophila IgG/IgM ELISA test is an enzyme linked immunosorbent assay to detect IgG/IgM antibodies to Legionella. Purified Legionella pneumopilla antigen (serogroups 1, 2, 3, 4, 5, 6) 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/IgM 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.
】!【. Predicate Device
The Legionella pneumophila IgG/IgM ELISA test is substantially equivalent to BioWhitttaker's Legionella STAT test. Equivalence is demonstrated by the following comparative results:
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Performance Characteristics
- Relative sensitivity and specificity. The Legionella pneumophila LyG/ IgM EL.ISA was evaluated relative to Legionella Stat at two different sites. The first site was a commercial R&D lab located in Maryland. Thirty three single IFA positive sera from an outbreak and samples routinely submitted for Legionella testing were tested. The study are summarized in Table 3.
Table 3 Comparison of Legionella pneumophila IgG/IgM ELISA and Legionella IFA
Wampole Legionella pneumophila IgG/IgM ELISA
| eq | Total | ||||
|---|---|---|---|---|---|
| + ≥256 | 27 | ﻢ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤﺴﺘﻮﻯ ﺍﻟﻤ | 33 | ||
| IFA | - >256 | 0 | 0 | 0 | () |
| Total | 27 | ﻢ ﺍﻟﻤﺮﺍﺟﻊ | 3 | 33 |
| Relative Sensitivity = 27/30 = 90.00% | 95% Confidence interval = 79.0% - 100% |
|---|---|
| Relative Specificity = NA | 95% Confidence interval = NA |
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 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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Wampole Legionellu pneumophila IgG/IgM ELISA
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The second site was a clinical laboratory located in Pennsylvania. Seventy two prospective serum for Legionella testing were tested. The results of the study are summarized in Table 4.
Table 4 Comparison of Legionella pneumophila IgG/IgM ELISA and Legionella IFA
| + | eq | - | Total | ||
|---|---|---|---|---|---|
| IFA | + ≥256 | 2 | 0 | 0 | 2 |
| - <256 | 1 | 2 | 67 | 70 | |
| Total | 3 | 2 | 67 | 72 |
| Relative Specificity = 67/68 = 98.53% | 95% Confidence interval = 95.6% - 100% |
|---|---|
| Relative Agreement = 69/70 = 98.57% | 95% Confidence interval = 95.7% - 100% |
Equivocals were not included in the above calculations. The 95% confidence intervals were calculated using the normal method
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Seven different sera were assayed at two different sites to determine the 2. Precision. precision of the assay. An additional three sera were tested at site 1. Each sera was tested ten times each, on three different days at each of the two study sites. The intra and inter assay precision for each site is presented in Tables 5 and 6 The inter-site coefficient of variation (CV) for each serum is presented in table 7.
Table 5 Legionella pneumophila IgG/IgM 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 | 3.17 | 0.138 | 4.35% | 3.55 | 0.235 | 6.62% | 3.41 | 0.349 | 10.2% | 3.42 | 0.305 | 8.92% |
| 2 | 2.44 | 0.244 | 10.0% | 2.66 | 0.267 | 10.0% | 2.41 | 0.127 | 5.27% | 2.50 | 0.247 | 9.88% |
| 3 | 2.49 | 0.322 | 12.9% | 2.78 | 0.240 | 8.63% | 2.81 | 0.332 | 11.8% | 2.70 | 0.327 | 12.1% |
| 4 | 1.22 | 0.180 | 14.8% | 1.36 | 0.131 | 9.63% | 1.16 | 0.125 | 10.8% | 1.25 | 0.164 | 13.1% |
| 5 | 0.50 | 0.051 | 10.2% | 0.56 | 0.042 | 7.50% | 0.53 | 0.041 | 7.74% | 0.53 | 0.050 | 9.43% |
| 6 | 0.18 | 0.025 | 13.9% | 0.21 | 0.023 | 11.0% | 0.20 | 0.031 | 15.5% | 0.20 | 0.030 | 15.0% |
| 7 | 0.28 | 0.039 | 13.9% | 0.34 | 0.046 | 13.5% | 0.33 | 0.048 | 14.6% | 0.32 | 0.051 | 15.9% |
| 8 | 1.02 | 0.051 | 5.00% | 1.13 | 0.039 | 3.45% | 1.19 | 0.044 | 3.70% | 1.11 | 0.084 | 7.57% |
| 9 | 0.85 | 0.053 | 6.24% | 0.92 | 0.025 | 2.72% | 0.99 | 0.043 | 4.34% | 0.92 | 0.069 | 7.50% |
| 10 | 0.96 | 0.067 | 6.98% | 1.05 | 0.056 | 5.33% | 1.11 | 0.094 | 8.47% | 1.03 | 0.122 | 11.20% |
| HPC* | 3.64 | .0402 | 11.05% | |||||||||
| CAL** | 1.44 | 0.122 | 8.44% | |||||||||
| LPC* | 1.49 | 0.195 | 13.11% | |||||||||
| NC* | 0.18 | 0.052 | 28.97% |
- = = 17 ** n = 51
Table 6 Legionella pneumophila IgG/IgM ELISA Intra and Inter Assay Precision Study 2
| Assay 1 (n=10) | Assay 2 (n=10) | Assay 3 (n=10) | Inter-Assay(n=30) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Sera# | X | SD | X | SD | CV | X | SD | CV | X | SD | CV |
| 1 | 2.80 | 0.246 | 2.66 | 0.165 | 6.20% | 3.08 | 0.245 | 7.95% | 2.85 | 0.272 | 9.54% |
| 2 | 3.10 | 0.343 | 3.05 | 0.276 | 9.05% | 3.14 | 0.259 | 8.25% | 3.10 | 0.293 | 9.45% |
| 3 | 3.31 | 0.392 | 3.17 | 0.220 | 6.94% | 3.38 | 0.214 | 6.33% | 3.31 | 0.289 | 8.73% |
| 4 | 1.10 | 0.135 | 1.15 | 0.131 | 11.4% | 1.18 | 0.142 | 12.0% | 1.16 | 0.138 | 11.9% |
| 5 | 0.56 | 0.060 | 0.58 | 0.053 | 9.14% | 0.59 | 0.036 | 6.10% | 0.58 | 0.050 | 8.62% |
| 6 | 0.28 | 0.016 | 0.26 | 0.013 | 5.00% | 0.29 | 0.020 | 6.90% | 0.28 | 0.020 | 7.14% |
| 7 | 0.29 | 0.018 | 0.28 | 0.020 | 7.14% | 0.31 | 0.023 | 7.42% | 0.29 | 0.023 | 7.93% |
| HPC* | 3.16 | 0.092 | 2.91% | ||||||||
| CAL** | 1.45 | 0.060 | 4.11% | ||||||||
| LPC* | 1.68 | 0.190 | 11.29% | ||||||||
| NC* | 0.35 | 0.121 | 34.44% | ||||||||
| * n = 5 |
홈
** n = 15
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Table 7 Legionella pneumophila IgG/IgM ELISA Inter Site Precision Study
| Inter Site (n=60) | ||||||
|---|---|---|---|---|---|---|
| Sera # | X | SD | CV | # positive | #equ | #negative |
| 1. | 3.13 | 0.406 | 13.0% | 60 | 0 | 0 |
| 2. | 2.80 | 0.403 | 14.4% | 60 | 0 | 0 |
| 3. | 3.00 | 0.431 | 14.4% | 60 | 0 | 0 |
| 4. | 1.21 | 0.158 | 13.1% | 43 | 16 | 1 |
| 5. | 0.56 | 0.055 | 9.82% | 0 | 0 | 60 |
| 6. | 0.24 | 0.046 | 19.2% | 0 | 0 | 60 |
| 7. | 0.30 | 0.040 | 13.3% | 0 | 0 | 60 |
| 8.* | 1.11 | 0.084 | 7.57% | 19 | 11 | 0 |
| 9.* | 0.92 | 0.069 | 7.50% | 0 | 20 | 10 |
| 10.* | 1.03 | 0.122 | 11.20% | 8 | 20 | 2 |
| HPC** | 3.42 | 0.401 | 11.75% | 9 | 0 | 0 |
| CAL*** | 1.45 | 0.069 | 4.77% | 27 | 0 | 0 |
| LPC** | 1.56 | 0.240 | 15.46% | 9 | 0 | 0 |
| NC** | 0.27 | 0.124 | 45.68% | 0 | 0 | 9 |
- n = 30 ** n = 9 *** n = 27
X = Mean SD = standard deviation CV = coefficient of variation = SD/X x 100
The methods in NCCLS EP5 were utilized for precision parameters.
4. IFA Paired Serum Analysis (CDC Panel).
The following information is from a serum panel tested at the CDC by IFA and confirmed to be serologically positive for an increase in titer from < 1:256 to >1:256. The sera were submitted to CDC for titer conformation. The results are presented as a means to convey further information on the performance of this assay with a masked serum panel. This does not imply an endorsement of the assay by the CDC.
The panel consists of 31 serum pairs showing a greater than 4 fold increase in IFA titer. Each serum pair was evaluated on the Legionella preumophila IgG/IgM ELISA assay to determine an seroconversion in antibody. Twenty nine pairs had a seroconversion thus giving a sensitivity of 29/31 = 93.5% in detecting seroconversions.
§ 866.3300
Haemophilus spp. serological reagents.(a)
Identification. Haemophilus spp. serological reagents are devices that consist of antigens and antisera, including antisera conjugated with a fluorescent dye, that are used in serological tests to identifyHaemophilus spp. directly from clinical specimens or tissue culture isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by bacteria belonging to the genusHaemophilus and provides epidemiological information on diseases cause by these microorganisms. Diseases most often caused byHaemophilus spp. include pneumonia, pharyngitis, sinusitis, vaginitis, chancroid venereal disease, and a contagious form of conjunctivitis (inflammation of eyelid membranes).(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.