(268 days)
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No
The device description and performance studies detail a standard ELISA assay, which is a biochemical test, not a software-based device utilizing AI/ML. There is no mention of AI, ML, or related concepts in the summary.
No.
This device is an in vitro diagnostic (IVD) test intended for the qualitative detection of antibodies to aid in the diagnosis of West Nile virus infection. It identifies a condition but does not provide therapy or treatment.
Yes
The device is intended for the "qualitative detection of IgG antibodies to West Nile virus in human serum and plasma" and "is intended as an aid in the presumptive laboratory diagnosis of West Nile virus infection in patients with clinical symptoms consistent with meningitis encephalitis". This explicitly states its purpose in diagnosing a medical condition.
No
The device description details a laboratory procedure involving physical reagents, microtiter plates, incubations, washing steps, and reading results on an ELISA reader, indicating it is a hardware-based in vitro diagnostic device, not software-only.
Yes, this device is an IVD (In Vitro Diagnostic).
Here's why:
- Intended Use: The intended use explicitly states it's for the "qualitative detection of IgG antibodies to West Nile virus in human serum and plasma". This is a test performed in vitro (outside the body) on a biological sample (serum and plasma) to provide information about a patient's health status (presence of antibodies indicating infection).
- Device Description: The description details a laboratory procedure (ELISA) involving the use of reagents and a microtiter plate to analyze patient samples. This is characteristic of an in vitro diagnostic test.
- Performance Studies: The document includes detailed performance studies such as repeatability, reproducibility, analytical specificity, interference, assay cut-off, and clinical studies. These are standard evaluations for IVD devices to demonstrate their accuracy and reliability.
- Predicate Device: The mention of a "Predicate Device" (K031953; Focus Diagnostics West Nile Virus IgG DxSelect™) is a strong indicator that this device is being compared to an already cleared or approved IVD device, which is a common practice in the regulatory process for new IVDs.
- Reference Methods: The use of PRNT (Plaque Reduction Neutralization Test) as a confirmation method is a standard practice for serological testing of West Nile virus, further supporting its role as a diagnostic tool.
All these elements align with the definition and characteristics of an In Vitro Diagnostic device.
N/A
Intended Use / Indications for Use
The EUROIMMUN Anti-West Nile Virus ELISA (IgG) is intended for the qualitative detection of IgG antibodies to West Nile virus in human serum and plasma (K+EDTA, Li+-heparin). This test is intended as an aid in the presumptive laboratory diagnosis of West Nile virus infection in patients with clinical symptoms consistent with meningitis encephalitis, in conjunction with other laboratory and clinical findings. Positive results must be confirmed by the plaque reduction test (PRNT) or by using the current CDC guidelines for diagnosis of this disease.
The assay characteristics have not been established for testing cord blood, neonates, prenatal screening, and general population screening of patients without symptoms of meningoencephalitis. This assay is not FDA cleared or approved for testing blood or plasma donors.
Warning: Cross-reactivity with IgG to Dengue, Chikungunya, Zika and Tick-borne Encephalitis (TBE) viruses has been observed with the EUROIMMUN Anti-West Nile Virus ELISA (IgG). Reactive results must be reported with a caution statement regarding possible IgG cross-reactivity with other flaviviruses.
Product codes (comma separated list FDA assigned to the subject device)
NPO
Device Description
Patient samples are diluted 1:101 in sample buffer, 100 ul of each diluted patient sample and pre-diluted controls and the calibrator are added to the antigen coated microtiter wells and incubated for 60 minutes at +37°C. After incubation the microtiter well strips are washed 3 times with wash buffer to remove unbound antibodies and 100 ul of the anti-human IgG enzyme conjugate reagent is added to each microtiter well. After an additional 30-minutes incubation at room temperature, the microtiter wells are again washed 3 times with wash buffer to remove any unbound enzyme conjugate and 100 ul of the chromogen substrate is added. The strips are incubated for 15 minutes at room temperature and 100 ul stop solution is added. The microtiter plates are placed in an ELISA reader and read at a wavelength of 450 nm and a reference wavelength of between 620 nm and 650 nm within 30 minutes.
The test kit contains 12 microtiter strips each with 8 break-off reagent wells coated with West Nile virus antigens. In the first reaction step, diluted patient samples, callbrator and controls are incubated in the wells. Anti-West Nile virus antibodies will bind to the antigens coated in the microtiter wells are washed to remove any unbound proteins and non-specific antibodies. In a second reaction step, rabbit anti-human IgG HRP enzyme conjugate is added to each well. The enzyme conjugate will bind to any wells that have human IgG binding to the West Nile virus antigen. The wells are washed to remove any unbound HRP enzyme conjugate. 3,3,5,5 tetramethylbenzidine (TMB) enzyme substrate is added. If the HRP enzyme is present in the well (positive reaction), the HRP enzyme will react with the TMB substrate and produce a blue color. After an additional incubation time to allow the color development, a stop solution is added which turns the blue color yellow and inhibits further color development to allow for a stable spectrophotometric reading. The test strips are placed in a microplate reader and the optical density of the color is measured. The amount of antigen specific bound antibody is proportional to the color intensity.
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
The assay characteristics have not been established for testing cord blood, neonates, prenatal screening, and general population screening of patients without symptoms of meningoencephalitis.
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)
Repeatability/Reproducibility:
Repeatability: Panel of 7 members (natural patient samples seropositive at different concentrations). 42 determinations per sample performed in 14 different runs on 7 different days (2 runs per day, 3 replicates per run). Total %CV ranged from 6.1% to 13.3%.
Reproducibility: Panel of 7 members. 60 determinations per sample performed at 3 different sites (in-house, 2 external laboratories) for 5 days (2 runs per day, 2 replicates per run). Total %CV ranged from 10.1% to 16.3%.
Analytical Specificity/Cross Reactivity:
Cross Reactivity: 910 serologically characterized seropositive specimens from patients with diseases other than WNV. Overall % Negative: 82.0%. High cross-reactivity observed with Anti-Dengue virus (13.8% Negative), Anti-Chikungunya virus (68.1% Negative), Anti-TBE virus (72.0% Negative), and Anti-Zika virus (0.0% Negative).
Interferences: Hemolytic, lipemic, and icteric samples showed no influence up to specific concentrations.
Assay Cut-off:
Based on 18 sera from clinically characterized positive WNV patients and 150 sera from normal healthy blood donors from a non-endemic region. ROC analysis showed optimal sensitivity (100.0%) and specificity (100.0%) at OD 0.475.
Using the cut-off of ratio 1.0 and borderline range of ratio 0.8 to 1.1: sensitivity of 100.0% (95% C.I.: 81.5 - 100.0%) and specificity of 98.7% (95% C.I.: 95.3 - 99.8%; if borderline samples counted as positive).
Clinical Study I:
Type: Prospective clinical study.
Sample size: 152 samples from patients suspected of West Nile Virus infection (81 men, 71 women, age 6 to 85 years, mean 49 years).
EUROIMMUN Anti-West Nile Virus ELISA (IgG) vs predicate assay: Positive agreement 93.3% (42/45), 95% C.I. 81.7-98.6%; Negative agreement 94.4% (101/107), 95% C.I. 88.2-97.9%.
Subset of 27 presumptive positives by predicate tested by PRNT and EUROIMMUN Anti-West Nile Virus ELISA (IgG): Sensitivity 92.6% (25/27), 95% C.I. 75.7-99.1%.
Clinical Study II:
Type: Clinical study.
Sample size: 401 serum samples collected prospectively from patients suspected of West Nile Virus infection (195 men, 206 women, age 3 to 102 years, mean 47 years).
EUROIMMUN Anti-West Nile Virus ELISA (IgG) vs Predicate ELISA: Positive agreement 95.6% (43/45), 95% C.I. 84.9-99.5%; Negative agreement 98.9% (352/356), 95% C.I. 97.1-99.7%.
Clinical Study III:
Type: Retrospective clinical study.
Sample size: 295 serum samples (200 from major outbreaks of West Nile fever in South Africa in 1974 and 1984).
EUROIMMUN Anti-West Nile Virus ELISA (IgG) vs RKI Anti-West Nile Virus PRNT: Positive agreement 99.5% (194/195), 95% C.I. 97.2-100.0%; Negative agreement 97.0% (97/100), 95% C.I. 91.5-99.4%.
Matrix Comparison (Serum vs Plasma):
Sample: 5 different sets of normal blood donor sample pairs (serum, EDTA plasma, Li-heparin plasma) spiked with 5 different positive serum samples.
Result: Passing-Bablok regression showed equivalence of concentrations between serum and corresponding plasma matrices. R2 above 0.975, % recovery compared to serum (100%) in range of 92% to 109%.
Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)
Assay Cut-off:
Sensitivity: 100.0% (95% C.I.: 81.5 - 100.0%)
Specificity: 98.7% (95% C.I.: 95.3 - 99.8%) (if borderline samples counted as positive)
Clinical Study I:
Positive agreement: 93.3% (42/45), 95% C.I. 81.7-98.6%
Negative agreement: 94.4% (101/107), 95% C.I. 88.2-97.9%
Sensitivity (vs PRNT): 92.6% (25/27) 95% C.I. 75.7-99.1%
Clinical Study II:
Positive agreement: 95.6% (43/45), 95% C.I. 84.9-99.5%
Negative agreement: 98.9% (352/356), 95% C.I. 97.1-99.7%
Clinical Study III:
Positive agreement: 99.5% (194/195), 95% C.I. 97.2-100.0%
Negative agreement: 97.0% (97/100), 95% C.I. 91.5-99.4%
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.
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).
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§ 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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Image /page/0/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular border with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" written around it. Inside the circle is an abstract symbol that resembles a stylized caduceus or a series of interconnected human profiles. The logo is black and white.
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
August 12, 2016
EUROIMMUN US, Inc. Michael Locke Director of Regulatory Affairs 1 Bloomfield Ave. Mountain Lakes, NJ 07046
Re: K153303
Trade/Device Name: EUROIMUN Anti-West Nile Virus ELISA (IgG) Regulation Number: 21 CFR 866.3940 Regulation Name: West Nile Virus Serological Reagent Regulatory Class: Class II Product Code: NPO Dated: July 8, 2016 Received: July 12, 2016
Dear Mr. Locke:
This letter corrects our substantially equivalent letter of August 10, 2016.
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. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. 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
1
CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
If you desire specific advice for your device on our labeling regulation (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to
http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely,
Stephen J. Lovell -S for
Uwe Scherf, M.Sc., Ph.D. Director Division of Microbiology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health Enclosure
2
Indications for Use
510(k) Number (if known) K153303
Device Name
EUROIMMUN Anti-West Nile Virus ELISA (IgG)
Indications for Use (Describe)
The EUROIMMUN Anti-West Nile Virus ELISA (IgG) is intended for the qualitative detection of IgG antibodies to West Nile virus in human serum and plasma (K+EDTA, Li+-heparin). This test is intended as an aid in the presumptive laboratory diagnosis of West Nile virus infection in patients with clinical symptoms consistent with meningitis encephalitis, in conjunction with other laboratory and clinical findings. Positive results must be confirmed by the plaque reduction test (PRNT) or by using the current CDC guidelines for diagnosis of this disease.
The assay characteristics have not been established for testing cord blood, neonates, prenatal screening, and general population screening of patients without symptoms of meningoencephalitis. This assay is not FDA cleared or approved for testing blood or plasma donors.
Warning: Cross-reactivity with IgG to Dengue, Chikungunya, Zika and Tick-borne Encephalitis (TBE) viruses has been observed with the EUROIMMUN Anti-West Nile Virus ELISA (IgG). Reactive results must be reported with a caution statement regarding possible IgG cross-reactivity with other flaviviruses.
Type of Use (Select one or both, as applicable)
∑ Prescription Use (Part 21 CFR 801 Subpart D)
| Over-The-Counter Use (21 CFR 801 Subpart C)
PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON A SEPARATE PAGE IF NEEDED.
FOR FDA USE ONLY
Concurrence of Center for Devices and Radiological Health (CDRH) (Signature)
3
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510(k) SUBSTANTIAL EQUIVALENCE
510(k) Number
Applicant
EUROIMMUN US INC. 1 Bloomfield Ave., Mountain Lakes, New Jersey 07046 Phone: 800-913-2022 Fax: 973-656-1098
Contact: Michael Locke Director of Regulatory Affairs & Quality Management 1 Bloomfield Ave., Mountain Lakes, New Jersey 07046 Phone: 800-913-2022 Fax: 973-656-1098
Product Name
EUROIMMUN Anti-West Nile Virus ELISA (IgG)
Device Identification
Regulation: 21 CFR 866.3940 (West Nile virus serological reagents) Classification: Class II Product Code: NOP Panel: Microbiology
Substantial Equivalence Information:
Comparison to Predicate Device
Similarities
Antigen
| New Device | Predicate Device | |
|---|---|---|
| Similarities | ||
| Item | EUROIMMUN Anti-West Nile Virus ELISA | |
| (IgG) (K153303) | Focus Diagnostics West Nile Virus | |
| IgG DxSelect™ (K031953) | ||
| Intended use | Detection of IgG class antibodies against West | |
| Nile virus | Same | |
| Assay format | Qualitative | Same |
| Technology | ELISA | Same |
| Assay platform | 96-well microtiter plates | Same |
| Antigen | Coated on microtiter plate | Same |
| Calibrators and Controls | 1 calibrator (cut-off) | |
| 2 controls: 1 positive; 1 negative | Same | |
| Conjugate | Anti-human IgG (rabbit) labelled with | |
| horseradish peroxidase | Same | |
| Substrate | TMB | Same |
| Wash buffer | 10x concentrate | Same |
| Serum sample dilution | 1:101 | Same |
| Procedure | Sample incubation with micro-well antigen | |
| coated plate, followed by a wash step, | ||
| incubation with an anti-human IgG enzyme | ||
| conjugate; wash step, incubation with | ||
| substrate; stopping of the reaction with stop | ||
| solution, photometric reading. | Same | |
| Differences | ||
| Item | New Device | Predicate Device |
| Recombinant, detergent-extracted
| Recombinant West Nile virus
5
| | glycoprotein E of West Nile virus from the
membrane fraction of human cells,
inactivated using high temperatures and
gamma radiation; effectiveness of
inactivation tested by culture | antigen |
|---------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------|
| Stop solution | 0.5 M sulphuric acid | 1 M sulfuric acid |
| Reagent preparation | All reagents, calibrator and controls are ready
to use, except for the wash buffer. | Calibrator and controls require
dilution before use. |
| Sample matrix | Serum or plasma (EDTA, Li-heparin), CSF | Serum |
| Reported results | Ratio | Index |
| Cut-off levels | Ratio
Result | Index
Result |
| | 1.1
positive | > 1.50
positive |
Intended Use
The EUROIMMUN Anti-West Nile Virus ELISA (IgM) is intended for the qualitative detection of IgM antibodies to West Nile virus in human serum and plasma (K -EDTA, Li -heparin). This test is intended as an aid in the presumptive laboratory diagnosis of West Nile virus infection in patients with clinical symptoms consistent with meningitis/encephalitis, in conjunction with other laboratory and clinical findings. Positive results must be confirmed by the plaque reduction neutralization test (PRNT) or by using the current CDC guidelines for diagnosis of this disease.
The assay characteristics have not been established for testing cord blood, neonates, prenatal screening, and general population screening of patients without symptoms of meningoencephalitis. This assay is not FDA cleared or approved for testing blood or plasma donors.
Warning: Cross-reactivity with IgG from Dengue, Chikungunya, Zika and Tick-borne Encephalitis (TBE) viruses has been observed with the EUROIMMUN Anti-West Nile Virus ELISA (IgG). Reactive results must be reported with a caution statement regarding possible IgG cross-reactivity with other flaviviruses.
Device Description
Patient samples are diluted 1:101 in sample buffer, 100 ul of each diluted patient sample and pre-diluted controls and the calibrator are added to the antigen coated microtiter wells and incubated for 60 minutes at +37°C. After incubation the microtiter well strips are washed 3 times with wash buffer to remove unbound antibodies and 100 ul of the anti-human IgG enzyme conjugate reagent is added to each microtiter well. After an additional 30-minutes incubation at room temperature, the microtiter wells are again washed 3 times with wash buffer to remove any unbound enzyme conjugate and 100 ul of the chromogen substrate is added. The strips are incubated for 15 minutes at room temperature and 100 ul stop solution is added. The microtiter plates are placed in an ELISA reader and read at a wavelength of 450 nm and a reference wavelength of between 620 nm and 650 nm within 30 minutes.
Test Principle
The test kit contains 12 microtiter strips each with 8 break-off reagent wells coated with West Nile virus antigens. In the first reaction step, diluted patient samples, callbrator and controls are incubated in the wells. Anti-West Nile virus antibodies will bind to the antigens coated in the microtiter wells are washed to remove any unbound proteins and non-specific antibodies. In a second reaction step, rabbit anti-human IgG HRP enzyme conjugate is added to each well. The enzyme conjugate will bind to any wells that have human IgG binding to the West Nile virus antigen. The wells are washed to remove any unbound HRP enzyme conjugate. 3,3,5,5 tetramethylbenzidine (TMB) enzyme substrate is added. If the HRP enzyme is present in the well (positive reaction), the HRP enzyme will react with the TMB substrate and produce a blue color. After an additional incubation time to allow the color development, a stop solution is added which turns the blue color yellow and inhibits further color development to allow for a stable spectrophotometric reading. The test strips are placed in a microplate reader and the optical density of the color is measured. The amount of antigen specific bound antibody is proportional to the color intensity.
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Performance Characteristics
Analytical Performance
Repeatability/Reproducibility
Repeatability: The repeatability of the EUROIMMUN Anti-West Nile Virus ELISA (IgG) was investigated by testing of a panel of 7 members prepared using natural patient samples seropositive at different concentrations. The inter-assay repeatability is based on 42 determinations per sample performed in 14 different runs on 7 different days (with 2 runs per day and 3 replicates per run). The data from the repeatability study is presented in the table below.
Repeatability
| No. | Mean
Ratio | Within-Run | | Within Day | | Between Days | | Total | |
|-----|---------------|------------|------|------------|-------|--------------|------|-------|-------|
| | | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| 1 | 0.1 | 0.01 | 7.4% | 0.01 | 13.2% | 0.00 | 1.3% | 0.01 | 13.3% |
| 2 | 0.4 | 0.02 | 5.3% | 0.04 | 11.7% | 0.03 | 6.9% | 0.05 | 13.6% |
| 3 | 0.8 | 0.03 | 4.2% | 0.07 | 9.7% | 0.00 | 0.0% | 0.07 | 9.7% |
| 4 | 0.9 | 0.03 | 3.7% | 0.09 | 10.4% | 0.00 | 0.0% | 0.09 | 10.4% |
| 5 | 1.2 | 0.05 | 4.2% | 0.08 | 6.7% | 0.00 | 0.0% | 0.08 | 6.7% |
| 6 | 2.2 | 0.08 | 3.8% | 0.14 | 6.1% | 0.00 | 0.0% | 0.14 | 6.1% |
| 7 | 3.7 | 0.06 | 1.7% | 0.20 | 5.5% | 0.13 | 3.6% | 0.24 | 6.6% |
| 8 | 4.1 | 0.14 | 3.5% | 0.23 | 5.7% | 0.09 | 2.3% | 0.25 | 6.1% |
Reproducibility: The reproducibility of the EUROIMMUN Anti-West Nile Virus ELISA (IgG) was investigated by testing of a panel of 7 members prepared using natural patient samples seropositive at different concentrations. The reproducibility is based on 60 determinations per sample performed at 3 different sites (in-house; and 2 laboratories in the north-east) for 5 days with 2 runs per day and 2 replicates per run. The data from the reproducibility study is presented in the table below.
Reproducibility
| No. | Mean
Ratio | Within-Run | | Within Day | | Between Days | | Between Sites | | Total | |
|-----|---------------|------------|-------|------------|-------|--------------|------|---------------|------|-------|-------|
| | | SD | %CV | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| 1 | 0.1 | 0.010 | 14.1% | 0.011 | 15.0% | 0.005 | 6.4% | 0.004 | 5.3% | 0.012 | 16.3% |
| 2 | 0.7 | 0.072 | 11.0% | 0.096 | 14.7% | 0.000 | 0.0% | 0.063 | 9.7% | 0.096 | 14.7% |
| 3 | 0.8 | 0.062 | 8.0% | 0.075 | 9.8% | 0.017 | 2.2% | 0.043 | 5.7% | 0.077 | 10.1% |
| 4 | 0.8 | 0.070 | 8.3% | 0.098 | 11.6% | 0.000 | 0.0% | 0.069 | 8.1% | 0.098 | 11.6% |
| 5 | 1.1 | 0.089 | 7.8% | 0.119 | 10.5% | 0.000 | 0.0% | 0.079 | 7.0% | 0.119 | 10.5% |
| 6 | 2.2 | 0.211 | 9.7% | 0.211 | 9.7% | 0.060 | 2.7% | 0.010 | 0.5% | 0.219 | 10.1% |
| 7 | 4.3 | 0.405 | 9.4% | 0.436 | 10.1% | 0.000 | 0.0% | 0.161 | 3.7% | 0.436 | 10.1% |
Analytical Specificity/Cross Reactivity
Cross Reactivity: Cross Reactivity was investigated using 910 serologically characterized seropositive specimens from patients with diseases other than WNV. Each of the specimens included in the study was characterized with respect to disease state prior to analysis of the specimens with the EUROIMMUN Anti-West Nile Virus ELISA (IgG). Cross-reactivity across the flavivirus group is common (i.e., St. Louis encephalitis, Dengue 1, 2, 3 & 4; Murray Valley encephalitis, Japanese encephalitis, Yellow fever viruses and Zika virus); as well as persons vaccinated for flaviviruses.
Cross Reactivity
| No. | Panel | n | Anti-West Nile Virus ELISA (IgG) | ||
|---|---|---|---|---|---|
| Positive | Negative | % Negative | |||
| 1 | Anti-Adenovirus | 12 | 0 | 12 | 100.0% |
| 2 | Anti-Barmah Forest virus | 20 | 0 | 20 | 100.0% |
| 3 | Anti-Borrelia burgdorferi | 54 | 3 | 51 | 94.4% |
| 4 | Anti-Chikungunya virus | 72 | 23 | 49 | 68.1% |
| 5 | Anti-Chlamydia pneum. | 12 | 0 | 12 | 100.0% |
| 6 | Anti-CMV | 12 | 0 | 12 | 100.0% |
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| No. | Panel | n | Anti-West Nile Virus ELISA (IgG) | ||
|---|---|---|---|---|---|
| Positive | Negative | % Negative | |||
| 7 | Anti-Dengue virus | 58 | 50 | 8 | 13.8% |
| 8 | Anti-EBV | 60 | 2 | 58 | 96.7% |
| 9 | Anti-Hanta virus | 11 | 0 | 11 | 100.0% |
| 10 | Anti-Hepatitis virus | 32 | 0 | 32 | 100.0% |
| 11 | Anti-Helicobacter pylori | 12 | 0 | 12 | 100.0% |
| 12 | Anti-HSV-1 | 39 | 2 | 37 | 94.9% |
| 13 | Anti-Influenza A | 12 | 0 | 12 | 100.0% |
| 14 | Anti-Influenza B | 12 | 0 | 12 | 100.0% |
| 15 | Anti-Leptospira | 11 | 0 | 11 | 100.0% |
| 16 | Malaria/anti-Plasmodium falciparum | 8 | 0 | 8 | 100.0% |
| 17 | Anti-Measles virus | 12 | 0 | 12 | 100.0% |
| 18 | Anti-Mumps virus | 12 | 0 | 12 | 100.0% |
| 19 | Anti-Mycoplasma pneumoniae | 12 | 0 | 12 | 100.0% |
| 20 | Anti-Parainfluenza types 1-4 | 12 | 0 | 12 | 100.0% |
| 21 | Anti-Polio virus | 37 | 1 | 36 | 97.3% |
| 22 | Anti-Ross River virus | 20 | 1 | 19 | 95.0% |
| 23 | Anti-RSV | 12 | 0 | 12 | 100.0% |
| 24 | Anti-Rubella virus | 12 | 0 | 12 | 100.0% |
| 25 | Anti-TBE virus | 118 | 33 | 85 | 72.0% |
| 26 | Anti-Toxoplasma gondii | 9 | 0 | 9 | 100.0% |
| 27 | Anti-VZV | 32 | 0 | 32 | 100.0% |
| 28 | Anti-West Nile Virus IgM | 10 | 0 | 10 | 100.0% |
| 29 | Yellowfever virus immunization | 12 | 0 | 12 | 100.0% |
| 30 | Anti-Zika virus | 47 | 47 | 0 | 0.0% |
| 31 | Rheumatoid arthritis/polyarthritis/anti-CCP | 16 | 0 | 16 | 100.0% |
| 32 | Anti-Rheumatoid factor | 37 | 1 | 36 | 97.3% |
| 33 | Anti-nuclear autoantibodies | 33 | 1 | 32 | 97.0% |
| 34 | ANCA-associated small vessel vasculitides/ANCA | 6 | 0 | 6 | 100.0% |
| 35 | Celiac disease/anti-endomysium | 10 | 0 | 10 | 100.0% |
| 36 | Plasma cell myeloma | 14 | 0 | 14 | 100.0% |
| Total | 910 | 164 | 746 | 82.0% |
Interferences: Hemolytic, lipemic and icteric samples showed no influence on the result up to a concentration of 1000 mg/dl for hemoglobin, 2000 mg/dl for triglycerides and 40 mg/dl for bilirubin in testing with the EUROIMMUN Anti-West Nile Virus ELISA (IgG). Interferences to high protein (albumin), cholesterol, and intralipids were not investigated.
Assay Cut-off:
The recommended assay cut-off is based on OD results of 18 sera from clinically characterized positive West Nile virus patients, and of 150 sera from normal healthy blood donors from a non-endemic region (100 men, 50 women; mean age 39.9 years, age range 18 to 68 years). The samples were investigated using the EUROIMMUN Anti-West Nile Virus ELISA (IgG) and a ROC analysis was performed using the OD's obtained. The ROC analysis demonstrated optimal sensitivity (100.0%) and specificity (100.0%) at the OD value of 0.475. The calibrator was established at this cut-off OD.
The borderline range of ratio 0.8 to ratio 1.1 was established to cover at least 98% of the negative samples (148 of 150 samples) in the negative range.
Using the cut-off of ratio 1.0 and borderline range of ratio 0.8 to 1.1 with the positive and negative groups mentioned above, the EUROIMMUN Anti-West Nile Virus ELISA (IgG) showed a sensitivity of 100.0% (95% C.I.: 81.5 - 100.0%) with a specificity of 98.7% (95% C.I.: 95.3 - 99.8%; if borderline samples counted as positive).
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Clinical Study I:
A prospective clinical study was performed with 152 samples from patients suspected of West Nile Virus infection collected at hospitals and clinics across the US in 2015. The panel consisted of 81 men and 71 women, age ranged from 6 to 85 years with a mean age of 49 years. Each specimen was tested at one internal and two external sites with the EUROIMMUN Anti-West Nile Virus ELISA (IgG) in parallel with the predicate assay. Average of three results for each clinical specimen tested at three sites was considered to calculate the positive percent and negative percent agreement between the EUROIMMUN Anti-West Nile Virus ELISA (IgG) vs the predicate assay. The following results were obtained.
| | Serum
n = 152 | Predicate | | |
|------------------------------------------------|------------------|-----------|------------|----------|
| | | Positive | Borderline | Negative |
| EUROIMMUN Anti- West Nile
Virus ELISA (IgG) | Positive | 42 | 1 | 1 |
| | Borderline | 2 | 0 | 4 |
| | Negative | 1 | 0 | 101 |
| Positive agreement | 93.3% (42/45) | 95% C.I. | 81.7-98.6% | |
| Negative agreement | 94.4% (101/107) | 95% C.I. | 88.2-97.9% | |
Of the 45 presumptive positives by the predicate device, 27 samples were further tested by PRNT (Plaque Reduction Neutralization Test) and the EUROIMMUN Anti-West Nile Virus ELISA (IgG). The results are shown below.
| Serum
| n = 27 | PRNT Results | ||
|---|---|---|---|
| Positive | Borderline | Negative | |
| EUROIMMUN Anti- West Nile | |||
| Virus ELISA (IgG) | 25 | 0 | 0 |
| 1 | 0 | 0 | |
| 1 | 0 | 0 |
Sensitivity 92.6% (25/27) 95% C.I. 75.7-99.1%
Clinical Study II:
A study was performed at a clinical laboratory in the midwest, with 401 serum samples collected prospectively from patients suspected of west nile virus infection. The serum panel consisted of 195 men and 206 women, age ranged from 3 to 102 years with a mean age of 47 years. The samples were tested with the EUROIMMUN Anti-West Nile Virus ELISA (IgG) in parallel with the Predicate ELISA.
| Serum
| n = 152 | Predicate | |||
|---|---|---|---|---|
| Positive | Borderline | Negative | ||
| EUROIMMUN Anti- West Nile | ||||
| Virus ELISA (IgG) | Positive | 43 | 0 | 3 |
| Borderline | 1 | 0 | 1 | |
| Negative | 1 | 0 | 352 | |
| Positive agreement | 95.6% (43/45) | 95% C.I. | 84.9-99.5% | |
| Negative agreement | 98.9% (352/356) | 95% C.I. | 97.1-99.7% |
Clinical Study III:
A retrospective clinical study was performed in cooperation with the Robert Koch Institute (RKI), Berlin, Germany with 295 serum samples that included 200 samples from major outbreaks of West Nile fever in South Africa in 1974 and 1984. The samples were tested by the EUROIMMUN Anti-West Nile Virus ELISA (IgG). The results are shown below.
| Serum
| n = 295 | RKI Anti-West Nile Virus PRNT | ||
|---|---|---|---|
| Positive | Negative | ||
| EUROIMMUN Anti- West Nile | |||
| Virus ELISA (IgG) | Positive | 194 | 3 |
| Borderline | 0 | 0 | |
| Negative | 1 | 97 |
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| Positive agreement | 99.5% (194/195) | 95% C.I. | 97.2-100.0% |
|---|---|---|---|
| Negative agreement | 97.0% (97/100) | 95% C.I. | 91.5-99.4% |
Expected Values
Euroimmun assessed reactivity with 553 samples prospectively collected from US population. The samples consisted of 50% females, and 50% males The range of positivity of different populations from the US prospective studies with the EUROIMMUN Anti-West Nile Virus ELISA (IgG) test kit are presented below.
US Studies
| Age | n | Negative | Borderline | Positive | % Positive | 95% C.I. |
|---|---|---|---|---|---|---|
| 0-9 | 16 | 16 | 0 | 0 | 0.0 – 20.6% | |
| 10-19 | 32 | 30 | 0 | 2 | 6.3% (2/32) | 0.8 – 20.8% |
| 20-29 | 66 | 59 | 2 | 5 | 7.6% (5/66) | 2.5 – 16.8% |
| 30-39 | 86 | 74 | 1 | 11 | 12.8% (11/86) | 6.6 – 21.7% |
| 40-49 | 89 | 76 | 1 | 12 | 13.5% (12/89) | 7.2 – 22.4% |
| 50-59 | 100 | 79 | 2 | 19 | 19.0% (19/100) | 11.8 – 28.1% |
| 60+ | 164 | 121 | 2 | 41 | 25.0% (41/164) | 18.6 – 32.3% |
| total | 553 | 455 | 8 | 90 | 16.3% (90/455) | 13.3 – 19.6% |
Note: It is recommended that each laboratory determine its own normal range based on the population and equipment used.
Matrix Comparison (Serum vs Plasma)
The usability of plasma was investigated using sample pairs each of serum and corresponding plasma (EDTA. Li-heparin). As no real plasma sample pairs from patients containing anti-West Nile virus antibodies were available, the samples were created from 5 different sets of normal blood donor sample pairs (serum, EDTA plasma, Li-heparin plasma) that were (after drawing) spiked with 5 different positive serum samples. After spiking, the sample sets were further diluted and processed according to the package insert.
Passing-Bablok regression was calculated for the comparison of serum to plasma. The regression equation is near the ideal correlation (intercept 0; slope 1.0) indicating equivalence of concentrations between serum and the corresponding plasma matrices. Coefficients of determination were found to be above 0.975 and % recovery compared to serum was in the range of 92 to 109% (serum = 100%).
| EDTA plasma | Li-heparin plasma | |
|---|---|---|
| Determinations (n) | 20 | 20 |
| Concentration range (serum) | Ratio 0.6 - 4.1 | Ratio 0.6 - 4.1 |
| Concentration range (plasma) | Ratio 0.6 - 4.1 | Ratio 0.6 - 4.1 |
| Regression equation | ||
| (y = plasma, x = serum) | y = -0.01 + 1.02x | y = 0.04 + 0.96x |
| 95% C.I. of intercept | -0.05 - 0.02 | -0.11 - 0.15 |
| 95% C.I. of slope | 0.99 - 1.05 | 0.89 - 1.10 |
| Coefficient of determination R2 | 0.9983 | 0.9759 |
| Mean %recovery | 101 % | 100 % |
| Range of %recovery | 98 - 105 % | 92 - 109 % |
Matrix Comparison (serum vs plasma)
Conclusion
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.