(143 days)
The FlexSure® HP test for IgG antibodies to H. pylori in whole blood is a rapid, visually read, qualitative immunochromatographic method. The test is for use by health professionals as an aid in the diagnosis of H. pylori infection in patients with clinical signs and symptoms of gastrointestinal disease.
The FlexSure® HP test for IgG antibodies to H. pylori in whole blood is a rapid, visually read, qualitative immunochromatographic method.
The FlexSure® HP Test for IgG Antibodies to H. pylori in Whole Blood is a rapid, visually read, qualitative immunochromatographic method designed as an aid in diagnosing H. pylori infection in patients with gastrointestinal symptoms.
Here's an analysis of the acceptance criteria and the studies performed:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are not explicitly stated as target percentages in the provided text. However, the performance of the FlexSure® HP Whole Blood test is presented in comparison to a predicate device (FlexSure® HP Serum test) and a gold standard (histology and/or urease test), as well as within specific groups (symptomatic patients, volunteer blood donors). The "acceptance criteria" are implied by demonstrating substantial equivalence to the predicate and acceptable performance against the gold standard.
| Performance Metric | Acceptance Criteria (Implied by Predicate Performance) | FlexSure® HP Whole Blood Performance (Reported) - Symptomatic Patients | FlexSure® HP Whole Blood Performance (Reported) - Volunteer Blood Donors |
|---|---|---|---|
| Relative Sensitivity (vs. FlexSure® HP Serum) | 95% (FlexSure® HP Serum vs. ELISA) | 92% (without resolution) 95% (with resolution) | Not Determined (meaningful comparison not possible without H. pylori confirmation) |
| Relative Specificity (vs. FlexSure® HP Serum) | 94% (FlexSure® HP Serum vs. ELISA) | 91% (without resolution) 94% (with resolution) | 99% |
| Overall Agreement (vs. FlexSure® HP Serum) | 95% (FlexSure® HP Serum vs. ELISA) | 92% (without resolution) 95% (with resolution) | 97% |
| Relative Sensitivity (vs. Histology/Urease) | 92% (FlexSure® HP Serum vs. Histology/Urease) | 88% | Not Applicable |
| Relative Specificity (vs. Histology/Urease) | 76% (FlexSure® HP Serum vs. Histology/Urease) | 74% | Not Applicable |
| Overall Agreement (vs. Histology/Urease) | 84% (FlexSure® HP Serum vs. Histology/Urease) | 82% | Not Applicable |
| Within-site Reproducibility | Not explicitly stated | 96% | N/A |
| Between-site Reproducibility | Not explicitly stated | 89% | N/A |
2. Sample Sizes Used for the Test Set and Data Provenance
- Whole Blood Test Set (Symptomatic Patients): 173 patients
- Data Provenance: Multi-center trial at six different gastroenterology clinics located in the United States, Canada, and the United Kingdom. This indicates a prospective and multi-national study.
- Whole Blood Test Set (Volunteer Blood Donors): 233 volunteer blood donors
- Data Provenance: Not explicitly stated, but implies a prospective collection for this specific study.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not explicitly state the number of experts used for establishing the ground truth when comparing the FlexSure® HP Whole Blood test against histology and/or urease tests.
- Qualifications of Experts: Not specified. However, the use of "histology" and "urease test" implies analysis by qualified laboratory personnel, likely pathologists, gastroenterologists, or trained technicians, but specific qualifications (e.g., years of experience) are not provided.
4. Adjudication Method for the Test Set
- For comparisons against FlexSure® HP Serum test:
- An adjudication method was used to resolve discordant serological results. This involved using "histology and/or a urease test." The specific process (e.g., how conflicting histology vs. urease results were handled, or if multiple readings were done) is not detailed.
- For comparisons directly against histology and/or urease test:
- The "ground truth" was established by histology and/or urease test. No further adjudication of these primary methods is described within the context of the whole blood test performance.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not conducted. This device is a diagnostic test for H. pylori antibodies, not an imaging or interpretation aid for human readers in the way an AI would be.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, the studies presented are for the standalone performance of the FlexSure® HP Whole Blood test. It is a visually read, qualitative immunochromatographic method, which is inherently a standalone "algorithm" (the test strips chemical reaction and visual result) without a human-in-the-loop performance component in the traditional sense of AI-assisted diagnostics. The human simply reads the result produced by the device.
7. The Type of Ground Truth Used
- For comparison against the predicate device (FlexSure® HP Serum test): The ground truth for the predicate device itself was established by comparison with a commercial microwell ELISA serological test. For the FlexSure® HP Whole Blood test, the FlexSure® HP Serum test was used as a comparator, and discordant results were further resolved by histology and/or urease test (which are forms of pathology/diagnostic testing).
- For direct comparison of FlexSure® HP Whole Blood test: The ground truth was established by histology and/or urease test. These are direct diagnostic methods for H. pylori infection, often considered the gold standard.
8. The Sample Size for the Training Set
The provided text describes performance evaluation studies, not the development or training of the device. Therefore, a "training set" sample size for the FlexSure® HP Whole Blood test is not applicable or provided. The "basic methodology and format" were established previously with the FlexSure® HP Serum test.
9. How the Ground Truth for the Training Set Was Established
As no training set is described for the FlexSure® HP Whole Blood test, this information is not applicable or provided. The FlexSure® HP Serum test's performance characteristics, which presumably formed the basis for the FlexSure® HP Whole Blood test development, were established by comparison with a commercial microwell ELISA serological test, histology, and 13C-urea breath test.
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SmithKline Diagnostics, Inc.
Image /page/0/Picture/3 description: The image shows the text "JUN - 7 1988" in bold, black font. The text appears to be a date, with "JUN" representing the month of June, "7" representing the day, and "1988" representing the year. The text is slightly angled, with the right side appearing higher than the left.
510(k) SUMMARY OF SAFETY AND EFFECTIVENESS
FlexSure® HP Test for IgG Antibodies to H. pylori in Whole Blood
This 510(k) summary of safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990.
| Manufacturer: | SmithKline Diagnostics, Inc.225 Baypointe ParkwaySan Jose, CA 95134-1622Attention: Marshall C. McCarty |
|---|---|
| Proprietary Name: | FlexSure® HP |
| Classification Name: | Test for IgG antibodies to H. pylori in whole blood |
| Intended Use: | The FlexSure® HP test for IgG antibodies to H. pylori inwhole blood is a rapid, visually read, qualitativeimmunochromatographic method. The test is for use byhealth professionals as an aid in the diagnosis of H. pyloriinfection in patients with clinical signs and symptoms ofgastrointestinal disease. |
| Predicate Product: | FlexSure® HP Test for Serum IgG Antibodies to H. pylori;Manufactured by SmithKline Diagnostics, Inc. |
| PerformanceSummary: | The SKD FlexSure® HP Test for IgG Antibodies toH. pylori in Whole Blood is substantially equivalent to thepredicate device, FlexSure® HP Test for Serum IgGAntibodies to H. pylori (K934863). The performance of theFlexSure® HP whole blood product was verified bysensitivity, specificity and reproducibility and interferencestudies in symptomatic patients and volunteer blood donors,mainly asymptomatic individuals, not being treated forgastrointestinal disease. Refer to attached PERFORMANCECHARACTERISTICS. |
Marshall C. McCarty
Marshall C. McCarty
Marshall C. McCarty Manager, Regulatory Affairs
Facsimile: (408) 435-1953
1-il-96
Date
Date
000011
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FlexSure® HP Test for IgG Antibodies to H. pylori in Whole Blood
PERFORMANCE CHARACTERISTICS
The basic methodology and format for the FlexSure® HP Whole Blood test were established previously with the FlexSure® HP Serum test. The tests differ principally in the method for sample collection and application of the sample to the Test Card. Both tests are equally effective in determining the presence of IgG antibodies against H, pvlori.
FlexSure® HP Serum Test
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The performance characteristics of the FlexSure® HP Serum test were previously reported (Premarket Notification K934863) for a group of 551 individuals (196 symptomatic and 355 asymptomatic) by comparison with a commercial microwell ELISA serological test. After eliminating 15 samples from the calculations with indeterminate ELISA Values, in accordance with the manufacturer's instructions, the remaining 536 samples yielded a relative sensitivity of 95% (285/299), a relative specificity of 94% (222/237) and overall agreement of 95% (507/536). The FlexSure® HP Serum test was also compared with two other reference methods in this group of individuals: histology and 13C-urea breath test.
FlexSure® HP Whole Blood Test
The FlexSure® HP Whole Blood test was evaluated in a multi-center trial at six different gastroenterology clinics located in the United States, Canada and the United Kingdom. A group of 173 patients who presented with gastrointestinal symptoms were evaluated with the FlexSure® HP Whole Blood test, the FlexSure® HP Serum test and upper endoscopy where multiple biopsy specimens were studied by histology and/or a urease test.
Direct comparison of the FlexSure® HP Whole Blood test with the FlexSure® HP Serum test yielded a relative sensitivity of 92%, a relative specificity of 91% and overall agreement of 92% (Table 1). After resolution of discordant serological results by histology and/or a urease test, the FlexSure® HP Whole Blood test had a relative sensitivity of 95%, a relative specificity of 94% and overall agreement of 95%.
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FlexSure® HP Test for IgG Antibodies to H. pylori in Whole Blood
Table 1 FlexSure® HP Serum Test vs. FlexSure® HP Whole Blood Test Symptomatic Patients*
| FlexSure® HP Serum | |||
|---|---|---|---|
| + | - | Total | |
| FlexSure® HPWhole Blood | 98 | 6 | 104 |
| 8 | 61 | 69 | |
| 106 | 67 | 173 | |
| Relative Sensitivity: | 92% | ||
| Relative Specificity: | 91% | ||
| Overall Agreement: | 92% |
- without resolution of discordants by histology and/or urease test
In this same group of patients, the FlexSure® HP Whole Blood test was compared directly with histology and/or a urease test, yielding a relative sensitivity of 88%, a relative specificity of 74% and overall agreement of 82% (Table 2).
Comparison of the FlexSure® HP Serum test with histology and/or a urease test in these patients yielded similar results: a relative sensitivity of 92%, a relative specificity of 76% and overall agreement of 84%.
The relative specificity of any serological test, when compared directly with histology or urease tests, may be lower if the bacterium was previously eradicated or suppressed as a result of taking antimicrobial drugs in connection with other medical treatments. In addition, sampling errors may occur due to the patchy distribution of the bacteria in the gastric mucosa. It is known that atrophy of the gastric mucosa often develops in persons with chronic active gastritis due to long-term H. pylori infection. This may lead to reduced bacterial loads making it difficult to detect the bacterium by histology or urease tests.
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FlexSure® HP Test for IgG Antibodies to H. pylori in Whole Blood
Table 2 Histology and/or Urease Test vs. FlexSure® HP Whole Blood Test Symptomatic Patients
| Histology and/or Urease | |||
|---|---|---|---|
| + | - | Total | |
| FlexSure® HPWhole Blood + | 84 | 20 | 104 |
| - | 11 | 58 | 69 |
| 95 | 78 | 173 | |
| Relative Sensitivity: | 88% | ||
| Relative Specificity: | 74% | ||
| Overall Agreement: | 82% |
The FlexSure® HP Whole Blood test was further evaluated in a group of 233 volunteer blood donors and vielded a relative specificity of 99% and overall agreement of 97%
when compared with the FlexSware UD S when compared with the FlexSure® HP Serum test. Since diagnostic confirmation of H. pylori infection by a second method was not done in this volunteer group, a meaningful determination of relative sensitivity could not be made (Table 3).
Table 3 FlexSure® HP Serum Test vs. FlexSure® HP Whole Blood Test Volunteer Blood Donors
| FlexSure® HP Serum | ||||
|---|---|---|---|---|
| + | - | Total | ||
| FlexSure® HPWhole Blood | + | 41 | 1 | 42 |
| - | 7 | 184 | 191 | |
| 48 | 185 | 233 | ||
| Relative Sensitivity: | Not Determined | |||
| Relative Specificity: | 99% | |||
| Overall Agreement: | 97% |
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FlexSure® HP Test for IgG Antibodies to H. pylori in Whole Blood
Reproducibility
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Within- and between-site reproducibility of the FlexSure® HP Whole Blood test was done with fresh fingerstick blood samples from three volunteers with known levels of antibody to H. pylori (negative, low/borderline positive, positive). Each volunteer gave three fingerstick samples on each day of testing. The within-site reproducibility was 26/27 (96%) and the between-site reproducibility was 24/27 (89%); the reproducibility of the between-site sample sets was 9/9 for the negative, 9/9 for the positive and 6/9 for the low/borderline positive.
Interference
The FlexSure® HP Whole Blood test was evaluated for possible interference from visibly lipemic or hemolytic samples. Whole blood was obtained by venipuncture and stored in Vacutainer tubes containing EDTA. Each sample was spiked with cholesterol, triglycerides or hemoglobin to obtain concentrations above physiological levels. Blood samples that were positive or negative for IgG antibodies to H. pylori were run before and after spiking on the FlexSure® HP Whole Blood test. None of the biological substances tested interfered with the procedure or yielded inaccurate test results.
Cross Reactivity
The cross reactivity of the test was determined previously for the FlexSure® HP Serum test. Sera containing known levels of antibody against H. pylori were evaluated according to the method of Perez-Perez, et al., (Ann. Int. Med. 109:11-17, 1988) with the following bacteria:
| Campylobacter jejuni | Escherichia coli |
|---|---|
| Campylobacter fetus | Helicobacter mustelae |
| Campylobacter coli | Helicobacter pylori |
All species tested showed no cross reactivity, indicating that the test has high specificity for human antibodies against H. pylori. Helicobacter pylori was tested as a control and found to be reactive.
§ 866.3110
Campylobacter fetus serological reagents.(a)
Identification. Campylobacter fetus serological reagents are devices that consist of antisera conjugated with a fluorescent dye used to identifyCampylobacter fetus from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of diseases caused by this bacterium and provides epidemiological information on these diseases.Campylobacter fetus is a frequent cause of abortion in sheep and cattle and is sometimes responsible for endocarditis (inflammation of certain membranes of the heart) and enteritis (inflammation of the intestines) in humans.(b)
Classification. Class I (general controls).