(90 days)
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No
The device description and performance studies describe a standard ELISA assay for detecting antibodies. There is no mention of AI, ML, or any computational analysis beyond basic data processing for calculating results and performance metrics.
No.
Explanation: This device is an in vitro diagnostic (IVD) test, specifically an ELISA, intended for the qualitative detection of IgM antibodies to West Nile virus. Its purpose is to aid in the diagnosis of West Nile virus infection by identifying biomarkers, not to provide treatment or therapy.
Yes
Explanation: The device is intended for "qualitatively detecting IgM antibodies to West Nile virus in human serum" and is described as an "aid in the presumptive laboratory diagnosis of West Nile virus infection," directly indicating its use in diagnosing a medical condition.
No
The device is an Enzyme-linked immunosorbent assay (ELISA), which is a laboratory test that involves physical reagents and procedures, not solely software.
Yes, this device is an IVD (In Vitro Diagnostic).
Here's why:
- Intended Use: The "Intended Use / Indications for Use" section explicitly states that the device is "intended for qualitatively detecting IgM antibodies to West Nile virus in human serum." This is a classic description of an in vitro diagnostic test, as it involves testing a biological sample (human serum) outside of the body to diagnose or aid in the diagnosis of a disease (West Nile virus infection).
- Device Description: The "Device Description" further clarifies that it is an "Indirect Enzyme-linked immunosorbent assay for qualitatively detecting human serum IgM antibodies to West Nile virus." ELISA is a common technique used in IVD tests.
- Sample Type: The test uses "human serum," which is a biological sample.
- Purpose: The test is used "as an aid in the presumptive laboratory diagnosis of West Nile virus infection." This directly relates to diagnosing a medical condition.
- Care Setting: The intended user is a "Clinical laboratory," which is where IVD tests are typically performed.
All of these points align with the definition of an In Vitro Diagnostic device.
N/A
Intended Use / Indications for Use
The Focus Technologies West Nile Virus IgM Capture ELISA is intended for qualitatively detecting IgM antibodies to West Nile virus in human serum. In conjunction with the Focus Technologies West Nile Virus ELISA IgG, the test is indicated for testing persons having symptoms of meningioencephalitis, as an aid in the presumptive laboratory diagnosis of West Nile virus infection. Positive results must be tested using the background subtraction method (either on the initial test or on a repeat test). Positive results must be confirmed by neutralization test, or by using the current CDC guidelines for diagnosing West Nile encephalitis. This test is not intended for self-testing, and this test is not FDA cleared nor approved for testing blood or plasma donors. Assay performance characteristics have not been established for automated instruments.
Product codes (comma separated list FDA assigned to the subject device)
NOP
Device Description
Indirect Enzyme-linked immunosorbent assay for qualitatively detecting human serum IgM antibodies to West Nile virus.
Mentions image processing
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Mentions AI, DNN, or ML
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Input Imaging Modality
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Anatomical Site
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Indicated Patient Age Range
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Intended User / Care Setting
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Description of the training set, sample size, data source, and annotation protocol
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Description of the test set, sample size, data source, and annotation protocol
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Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Study Site 4: Focus Reactivity with Non-Flavivirus Test Samples (n=476)
This study assessed the device's reactivity with 476 samples prospectively collected from North America in August 2003. These samples were submitted to a clinical laboratory in Southern California for non-flavivirus tests. Positive samples were tested with a CDC WNV IgM ELISA and/or the CDC WNV IgG ELISA.
Without Background Subtract (Summary from table):
Total samples: 476
Overall % Positive: 1.1% (5/476) with 95% CI 0.3-2.4%
With Background Subtract (Summary from table):
Overall % Positive: 0.4% (2/476) with 95% CI 0.1-1.5%
Study Site 1: Focus Reactivity with Encephalitis/Meningitis Patients (n=300)
A state department of health laboratory in the northeastern U.S. assessed the device's reactivity with 300 samples from encephalitis/meningitis patients. The reference methods were the CDC IgM ELISAs and a plaque reduction neutralization test (PRNT) for West Nile virus. 44 patients were confirmed positive and 252 had presumptive assay results (4 indeterminant samples were excluded from 256).
Without Background Subtract:
Clinical sensitivity (confirmed positive, n=44): 90.9% (40/44) with 95% CI 78.3-97.5%. (Includes 2 Focus equivocals calculated as negatives).
Agreement with presumptive CDC IgM ELISA (presumed positive, n=2): Positive 100% (2/2) with 95% CI 15.8-100%.
Agreement with presumptive CDC IgM ELISA (presumed negative, n=250): Negative 99.6% (249/250) with 95% CI 97.8-100%. (Includes 1 Focus equivocal calculated as positive).
With Background Subtract:
Clinical sensitivity (confirmed positive, n=44): 93.2% (41/44) with 95% CI 78.3-97.5%. (Includes 1 Focus equivocal calculated as negative).
Agreement with presumptive CDC IgM ELISA (presumed positive, n=2): Positive 100% (2/2) with 95% CI 15.8-100%.
Agreement with presumptive CDC IgM ELISA (presumed negative, n=250): Negative 100% (250/250) with 95% CI 98.6-100%.
Study Site 2 & Study Site 4: Focus Reactivity with WNV PRNT Positives (n=75)
Focus (with background subtract) and a clinical laboratory (screening procedure) in the mid-western U.S. assessed the device's reactivity with 75 retrospective samples that were pre-screened positive by a West Nile virus native antigen ELISA and confirmed West Nile positive by PRNT.
Without Background Subtract (Study Site 2, n=75):
Serological sensitivity (WNV PRNT positive): 100% (75/75) with 95% CI 95.2-100%.
With Background Subtract (Study Site 2, n=70, 5 samples QNS):
Serological sensitivity (WNV PRNT positive): 100% (70/70) with 95% CI 94.9-100%.
Study Site 3: Focus Reactivity with West Nile IFA Negatives (n=103)
A clinical laboratory in the southwestern U.S. assessed reactive samples that were West Nile IFA negative.
Without Background Subtract:
Negative agreement with presumptive WNV IFA: 96.1% (99/103) with 95% CI 90.3-98.9%. (Includes one equivocal calculated as positive).
With Background Subtract:
Negative agreement with presumptive WNV IFA: 98.1% (101/103) with 95% CI 93.2-99.8%. (Includes one equivocal calculated as positive).
Study Site 4: Focus Reactivity with Suspected Encephalitis/Meningitis Patients (n=50)
Focus assessed the device's reactivity with 50 archived and masked samples from patients with suspected meningitis. One sample was confirmed positive by WNV PRNT, and 49 were presumptively negative (CDC ELISA) for arboviruses.
Without Background Subtract:
Serological sensitivity (CDC IgM ELISA positive and WNV PRNT positive, n=1): 100% (1/1) with 95% CI NA.
Negative agreement with presumptive CDC IgM ELISA (n=49): 98.0% (48/49) with 95% CI 89.1-99.9%.
With Background Subtract:
Serological sensitivity (CDC IgM ELISA positive and WNV PRNT positive, n=1): 100% (1/1) with 95% CI NA.
Negative agreement with presumptive CDC IgM ELISA (n=49): 100% (49/49) with 95% CI 92.7-100%.
Study Site 4: Focus Reactivity with Non-Flavivirus Test Samples (n=476)
Focus assessed the device's reactivity with 476 samples prospectively collected from North America during August 2003, submitted to a clinical laboratory in Southern California for infectious diseases. Positive samples were tested with a CDC WNV IgM ELISA. (Excludes four CDC ELISA IgM indeterminant samples from calculations).
Without Background Subtract:
Positive agreement with presumptive CDC IgM ELISA (n=3): 33.3% (1/3) with 95% CI 0.8-90.6%. (Includes 2 Focus equivocals).
Negative agreement with presumptive CDC IgM ELISA (n=469): 99.8% (468/469) with 95% CI 98.8-100%. (Includes 1 Focus equivocal included as positive).
With Background Subtract:
Positive agreement with presumptive CDC IgM ELISA (n=3): 66.7% (2/3) with 95% CI 9.4-99.2%.
Negative agreement with presumptive CDC IgM ELISA (n=469): 100% (469/469) with 95% CI 99.2-100%.
Focus Cross-reactivity
Focus (Study Site 4) and a state department of health laboratory (Study Site 1) assessed cross-reactivity with 75 sero-positive samples to other potentially cross-reactive pathogens.
Results are summarized in tables with and without background subtract.
Without background subtract, % positive ranged from 0.0% to 53.8%.
With background subtract, % positive ranged from 0.0% to 40.0%. St. Louis encephalitis virus was not tested with background subtract.
Focus Reproducibility
Assessed with and without background subtract at three sites for seven samples.
Without Background Subtract: Inter-Lab %CV ranged from 1.5 to 36.9.
With Background Subtract: Inter-Lab %CV for positive samples (BS22, BS3) were 2.1 and 1.2. Negative samples (BS1, BS6, BS2) and masked replicates (BS21, BS23)- which were positive in the assay but negative with background subtract- were reported as NA or negative %CV.
Specificity of the Focus WNV IgM Assay
Tested 15 sera positive for both WNV IgM and IgG. Treatment with 2-mercaptoethanol (2-ME) caused 100% (15/15) of samples to become IgM negative.
Sera Freeze-Thaw Study
Assessed impact of up to 5 repeated freeze-thaw cycles on 8 sera (5 positive, 3 negative). No changes in interpretation were found. Positive samples trended slightly towards increasing indices.
Reproducibility Studies
Included Inter-lot, Inter/Intra-assay, and Inter-laboratory Reproducibility.
Inter- & Intra-assay: Intra-assay %CV ranged from 1.5 to 3.4%; Inter-assay %CV ranged from 0.3 to 20.0%.
Inter-lot: Index %CV ranged from 0.4 to 3.6%.
Inter-Lab: Index %CV ranged from 2.3 to 13.2%.
Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)
See "Summary of Performance Studies" for specific sensitivity, negative agreement, positive agreement, and % positive values. General terms such as "clinical sensitivity", "agreement with presumptive CDC IgM ELISA", "serological sensitivity", "negative agreement with presumptive WNV IFA", and "% Positive" for cross-reactivity are reported. Reproducibility is measured by %CV.
Predicate Device(s): If the device was cleared using the 510(k) pathway, identify the Predicate Device(s) K/DEN number used to claim substantial equivalence and list them here in a comma separated list exactly as they appear in the text. List the primary predicate first in the list.
Focus Technologies Arbovirus IFA IgM (K913618), Focus Technologies HSV-2 ELISA (K993724), Focus West Nile Virus IgM Capture ELISA (K031952)
Reference Device(s): Identify the Reference Device(s) K/DEN number and list them here in a comma separated list exactly as they appear in the text.
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Predetermined Change Control Plan (PCCP) - All Relevant Information for the subject device only (e.g. presence / absence, what scope was granted / cleared under the PCCP, any restrictions, etc).
Not Found
§ 866.3940 West Nile virus serological reagents.
(a)
Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum, from individuals who have signs and symptoms consistent with viral meningitis/encephalitis. The detection aids in the clinical laboratory diagnosis of viral meningitis/encephalitis caused by West Nile virus.(b)
Classification. Class II (special controls). The special control is FDA's guidance entitled “Class II Special Controls Guidance Document: Serological Reagents for the Laboratory Diagnosis of West Nile Virus.” See § 866.1(e) for the availability of this guidance document.
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JUN 3 0 2004
14085
510(k) Summary of Safety and Effectiveness West Nile Virus IgM Capture ELISA Catalog No. EL0300M Prepared June 28, 2004 Page 1 of 8
| Applicant | Focus Technologies, Inc.
10703 Progress Way
Cypress, California 90630
USA |
|-----------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Establishment Registration
No. | 2023365 |
| Contact Person | Michael J. Wagner, Esq.
tel (714) 220-1900
fax (714) 995-6921
mwagner@focustechnologies.com |
| Summary Date | June 28, 2004 |
| Proprietary Name | West Nile Virus IgM Capture ELISA |
| Generic Name | West Nile Virus IgM Capture ELISA |
| Classification | West Nile Virus Serological Reagents
21 CFR §866.3940
Class II |
| Predicate Device | Focus Technologies Arbovirus IFA IgM (K913618)
Focus Technologies HSV-2 ELISA (K993724)
Focus West Nile Virus IgM Capture ELISA (K031952)
CDC West Nile Virus IgM Capture ELISA
West Nile Virus Plaque Reduction Neutralization Test |
Device Description
Indirect Enzyme-linked immunosorbent assay for qualitatively detecting human serum IgM antibodies to West Nile virus.
Intended Use
The Focus Technologies West Nile Virus IgM Capture ELISA is intended for qualitatively detecting IgM antibodies to West Nile virus in human serum. In conjunction with the Focus Technologies West Nile Virus ELISA IgG, the test is indicated for testing persons having symptoms of meningioencephalitis, as an aid in the presumptive laboratory diagnosis of West Nile virus infection. Positive results must be tested using the background subtraction method (either on the initial test or on a repeat test). Positive results must be confirmed by neutralization test, or by using the current CDC guidelines for diagnosing West Nile encephalitis. This test is not intended for self-testing, and this test is not FDA cleared nor approved for testing blood or plasma donors. Assay performance characteristics have not been established for automated instruments.
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Test Principle
In the Focus Technologies West Nile Virus IgM Capture ELISA, the polystyrene microwells are coated with anti-human antibody specific for IgM (u-chain). Diluted specimen samples and controls are incubated in the wells, and IgM present in the sample binds to the anti-human antibody (IgM specific reactants are removed by washing. Recombinant WNV antigen is then added to the wells and incubated, and, if anti-WNV IgM is present in the sample, the WNV antigen binds to the anti-WNV in the well.
Unbound WNV antigen is then removed by washing the well Mouse anti-flavivirus comjugated with horseradish peroxidase (HRPO) is then added to the wells and, if WNV antigen has been retained in the well by the anti-flavivirus in the sample, the mouse anti-flavivirus: HRPO binds to the WNV antigen in the wells. Excess conjugate is removed by washing. Enzyme substrate and chromogen are added, and the color is allowed to develop. After adding the Stop Reagent, the resultant color change is read by a spectrophotometer. The color intensity is compared to the Cut-off's to determine if antigen-specific IgM is present in the sample.
Background Subtract Procedure
All IgM reactive samples must be tested with the background subtract procedure to check for false positives caused by cross-reacting antibodies (e.g., RF and heterophilic antibodies) and other substances. Heterophile antibodies are antibodies that can be present in the patient specimen and can bind to animal antibodies (for example the Capture Wells contain rabbit antibody and the Anti-flavivirus Contains mouse antibody). The background subtract procedure detects false positives by testing initially positive samples with and without West Nile Antigen and comparing the reactivity. If heterophile antibodies are present in the sample, they will cross-link the Capture Well antiflavivirus Conjugate, and both wells will be reactive. If heterophile antibodies are absent, then only the well with Antigen will be reactive. The background subtraction method will not eliminate false positive results due to cross-reactive antibodies to other flaviviruses (e.g. St. Louis encephalitis, dengue etc).
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K040854 510(k) Summary of Safety and Effectiveness West Nile Virus IgM Capture ELISA Catalog No. EL0300M Prepared June 28, 2004 Page 3 of 8
Expected Values
The prevalence of West Nile antibodies varies depending age, geographic location, testing method used, and other factors. A community based serosurvey for West Nile infection conducted in New York in 2000 found that 0.2% (5/2433) of persons tested overall had antibodies indicating recent West Nile infection, and that 1.1% (2/176) of persons reporting a recent headache and fever had antibodies indicating a recent. West Nile infection. Two serosurveys conducted in New York City (NYC) in 1999 and 2000 showed that approximately 1 in 150 infections ( Trade/Device Name: Focus West Nile Virus IgM Capture ELISA Regulation Number: 21 CFR 866.3940 Regulation Name: West Nile Virus Serological Reagents Regulatory Class: Class II Product Code: NOP Dated: June 6, 2004 Received: June 8, 2004
Dear Mr. Wagner:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate 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) that do not require approval of a premarket approval application (PMA). 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 (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).
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This letter will allow you to begin marketing your device as described in your Section 510/k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 594-3084. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.
Sincerely yours,
Salazar
Sally A. Hojvat, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known):K040854
Device Name: Focus West Nile Virus IgM Capture ELISA
Indications For Use: The Focus Technologies West Nile Virus IgM Capture ELISA is intended for qualitatively detecting IgM antibodies to West Nile virus in human serum. In conjunction with the Focus Technologies West Nile Virus ELISA IgG, the test is indicated for testing persons having symptoms of meningioencephalitis, as an aid in the presumptive laboratory diagnosis of West Nile virus infection. Positive results must be tested using the background subtraction method (either on the initial test or on a repeat test). Positive results must be confirmed by neutralization test, or by using the current CDC quidelines for diagnosing West Nile encephalitis. This test is not intended for selftesting, and this test is not FDA cleared nor approved for testing blood or plasma donors. Assay performance characteristics have not been established for automated instruments.
Prescription Use
(Part 21 CFR 801 Subpart D)
AND/OR
Over-The-Counter Use (21 CFR 801 Subpart C)
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
Saga Atto 6/23/04
Division Sign-Off
Office of In Vitro Diagnostic Device Evaluation and Safety
KO40854 510(k) _
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