(84 days)
This Enzyme immunoassay is used for the quantitative estimation of non-protein bound thyroxine(Free T4) in human serum. This is an in vitro diagnostic device used to assist in the assessment of thyroid function.
The Biostride Free T4 EIA Test Kit is an in vitro enzyme immunoassay for the quantitative estimation of freeT4, thyroxine, in human serum. This Free T4 test is a colorimetric microtiter plate enzyme immunoassay (EIA).
Acceptance Criteria and Device Performance Study for Biostride Free T4 EIA Test Kit
1. Acceptance Criteria and Reported Device Performance
The Biostride Free T4 EIA Test Kit was evaluated against the Abbott AxSYM, a legally marketed predicate device. The primary acceptance criteria were demonstrating similar performance characteristics and excellent correlation of results.
| Metric | Acceptance Criteria (based on predicate device) | Reported Device Performance (Biostride Free T4 EIA Test Kit) |
|---|---|---|
| Correlation Coefficient (r) | Excellent correlation with predicate (Abbott AxSYM) | 0.96 |
| Intercept | Similar to predicate | 0.13 ng/dL |
| Slope | Similar to predicate | 0.91 |
| Precision (CVs) | Similar to predicate (Abbott system reported CVs between 2.10-9.9%) | 6%, 3% |
| Reproducibility (CVs) | Similar to predicate | 19%, 5%, 4% |
| Sensitivity | Similar to predicate (Abbott AxSYM: 0.04 ng/dL) | 0.08 ng/dL (defined as 2 SD from 0.0 g/dL calibrator) |
| Specificity to D-T4 | Similar to predicate (Abbott system: approximately 100%) | Approximately 100% |
Conclusion: The study demonstrated that the Biostride Free T4 EIA Test Kit met the acceptance criteria by showing similar performance characteristics and excellent correlation of results when compared to the Abbott AxSYM.
2. Sample Size and Data Provenance
- Sample Size for Test Set: 171 patient samples
- Data Provenance: Not explicitly stated, however, the context of clinical testing typically implies the samples were collected from a relevant patient population. (Prospective/Retrospective not specified)
3. Number of Experts and Qualifications for Ground Truth
Not applicable. This was a comparative study against a predicate device, not a study requiring expert interpretation for ground truth establishment. The ground truth was effectively the results obtained from the predicate device, which is an established clinical assay.
4. Adjudication Method for Test Set
Not applicable. The study involved direct comparison of quantitative results between two assays, not interpretation by multiple human readers requiring adjudication.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This study is for an in-vitro diagnostic device (EIA test kit), which generates quantitative results and does not involve human readers interpreting images or data in the same way an MRMC study would.
6. Standalone Performance Study
Yes, a standalone performance was done for the Biostride Free T4 EIA Test Kit by evaluating its precision, reproducibility, sensitivity, and specificity. However, these were then presented in comparison to the predicate device to establish substantial equivalence.
7. Type of Ground Truth Used
The "ground truth" for this study was essentially the quantitative Free T4 values obtained from the Abbott AxSYM, which is a widely accepted and legally marketed predicate device for Free T4 estimation. This can be considered a form of reference standard comparison.
8. Sample Size for Training Set
The document does not explicitly mention a separate "training set" or its size. In a device like an EIA test kit, the development and optimization (which might be analogous to "training") typically involve internal validation studies to establish the assay's performance characteristics, rather than a distinct "training set" of patient data in the machine learning sense. The described study focuses on validation against a predicate device.
9. How Ground Truth for Training Set was Established
As no explicit training set is mentioned in the provided text, the method for establishing its ground truth is also not detailed. Device development often relies on a combination of analytical validation, using prepared samples with known concentrations, and internal clinical samples.
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JUN 29 1998
K981243
Biostride, Inc.
510(k) Summary
This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of the SMDA 1990 and 21 CFR Part 807.92.
- Date of summary: April 2, 1998
Biostride Diagnostics Inc., 1201 Douglas Ave. Redwood City, CA 2. Submitted by: 94063 TEL 650-367-4954 FAX 650-364-4985 Contact: George Nokes or Laura Colin
Biostride Free T4 EIA Test, Test kit to determine the quantitative 3. Device Name: estimation of Free T4 in human serum
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Device Classification: Class II, 75-CEC, CFR (862.1695)
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Device description: The Biostride Free T4 EIA Test Kit is an in vitro enzyme immunoassay for the quantitative estimation of freeT4, thyroxine, in human serum. This Free T4 test is a colorimetric microtiter plate enzyme immunoassay (EIA).
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Intended Use: The Biostride Free T4 EIA Test is an in vitro enzyme immunoassay for the quantitative estimation of free T4, thyroxine, in human serum.
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Substantial Equivalence: The Biostride FT4 ElA was compared to the Abbott AxSYM.
The Biostride Free T4 test is a colorimetric microtiter plate enzyme immunoassay (EIA) for the estimation of Free T4 in human serum. Patient samples and rabbit Anti T4 are pipetted into a microtiter well coated with Goat-Anti-Rabbit IgG. After a 20 minute incubation T4-HRP tracer is added and incubated for 20 minutes, followed by asyash with tap water. The formation of blue color is obtained with the addition of the TMB/H2O2 substrate. 2N HCI is added to stop the enzyme/substrate reaction, giving a yellow color. Color intensity is measured as absorbance on a microtiter plate reader at 450 nm. The absorbance value is indirectly proportional to the concentration of Free T4 in the sample. The Abbott AxSYM is an MEIA, Microparticle Enzyme immunoassay, which combines human serum containing T4 and anti-T4 sheep microparticles. The T4 bound microparticles are transferred and irreversibly bound to a glass fiber matrix. The Abbott system uses an alkaline phosphatase conjugate tracer and a 4-Methylumbelliferyl Phosphate substrate. The Abbott method measures a fluorescent product, which is indirectly proportional to the concentration of Free T4. The Abbott system is an automated procedure including sample processing, testing and reporting.
43
Biostride, Inc.
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Both products have the same intended use, i.e., enzyme immunoassays for the quantitative estimation of Free T4 in human serum. Both test systems use several standard curve calibrators to interpret patient samples and report the result in ng/dL.
The products demonstrated similar performance characteristics and excellent correlation of results.
171 patient samples were evaluated to compare the results of the two tests. The correlation results were as follows:
| Intercept | Slope | Correlation Coefficient(r) |
|---|---|---|
| 0.13 ng/dL | 0.91 | 0.96 |
Performance Characteristics were similar in the two products as follows:
- Biostride demonstrated precision CVs of 6%, 3% and reproducibility CVs of I 9%. 5% and 4%. The Abbott system reported precision CVs between 2.10-9.9%
- 피 The sensitivity defined as the concentration of 2 SD from the 0.0 g/dL calibrator was 0.08ng/dL for Biostride and 0.04ng/dL for AxSYM.
- 피 Specificity to D-T4 was similar at approximately 100% for both products
Conclusion
The Biostride Free T4 EIA Test Kit and the Abbott AxSYM are substantially equivalent in performance characteristics, intended use, and assay principle.
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Food and Drug Administration 2098 Gaither Road Rockville MD 20850
JUN 2 9 1998
Janis Freestone Charlton Associates 1206 Sesame Drive Sunnyvale, California 94087
Re : K981243 Biostride Free T4 EIA Test Kit Requlatory Class: II Product Code: CEC June 9, 1998 Dated: Received: June 11, 1998
Dear Ms. Freestone:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). 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.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major requlations affecting your device can be found in the Code of Federal Requlations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General requlation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements Please note: concerning your device in the Federal Register. this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or requlations.
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Page 2
This letter will allow you to begin marketing your device as This letter will allow you co begt motification. The FDA described in your 510(k) premaince of your device to a legally marketed predicate device results in a classification for your marketed predicate device robated to proceed to the market.
device and thus, permits your device on our labeling device and thus, permicb your device for your device on our labeling in II you desire specific additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on Compliance at (3017-394 ising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to
the regulation entitled, "Misbranding by reference for information on your responsibilities under the Act may be Information on your responsible of Small Manufacturers Assistance obtained from the Division (800) 638-2041 or (301) 443-6597 or at its internet address "dsmo@fdadr.cdrh.fda.gov".
Sincerely yours,
Steven Autman
Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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INDICATIONS FOR USE STATEMENT
510k number (if known): K981243
Device Name: Biostride Free T4 EIA Test Kit
Indications for use:
This Enzyme immunoassay is used for the quantitative estimation of non-
protein bound thyroxine(Free T4) in human serum. This is an in vitro
diagnostic device used to assist in the assessment of thyroid function.
(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
(Division Sign-Off)
Division of Clinical Laboratory Devices
510(k) Number K98/243
Prescription Use (Per 21 CFR 801.109) OR
Over-The-Counter Use
(Optional Format 1-2-96)
§ 862.1695 Free thyroxine test system.
(a)
Identification. A free thyroxine test system is a device intended to measure free (not protein bound) thyroxine (thyroid hormone) in serum or plasma. Levels of free thyroxine in plasma are thought to reflect the amount of thyroxine hormone available to the cells and may therefore determine the clinical metabolic status of thyroxine. Measurements obtained by this device are used in the diagnosis and treatment of thyroid diseases.(b)
Classification. Class II.