Wielisa MPO ANCA Test Kit. An Enzyme Linked Immunosorbent Assay (ELISA) for the detection and semi-quantitation of IgG antibodies in human serum to MPO (Myeloperoxidase). The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of Microscopic polyangiitis.

Device Description

The Wielisa MPO ANCA Test Kit is an enzyme-linked immunosorbent assay (ELISA) for the detection and semi-quantitation of IgG antibodies to myeloperoxidase (MPO) in human sera. The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of microscopic polyangiitis. FOR IN VITRO DIAGNOSTIC USE.

The wells of the microtiter strips are coated with purified myeloperoxidase. During the first incubation, specific antibodies in diluted serum, will bind to the antigen coating.

The wells are then washed to remove unbound antibodies and other components. A conjugate of alkaline phosphatase-labeled antibodies to human IgG binds to the antibodies in the wells in this second incubation.

After a further washing step. detection of specific antibodies is obtained by incubation with substrate solution. The amount of bound antibodies correlates to the color intensity and is measured in terms of absorbance (optical density (OD)). The absorbance is then calculated against a calibrator curve and the results are given in arbitrary units.

AI/ML Overview

This submission describes the Wielisa MPO ANCA Test Kit, an ELISA for detecting and semi-quantitating IgG antibodies to myeloperoxidase (MPO) in human sera, used as an aid in diagnosing microscopic polyangiitis. While the document doesn't explicitly state "acceptance criteria", it provides performance metrics that serve as the basis for demonstrating substantial equivalence to a predicate device. The studies described assess the device's clinical sensitivity and specificity, relative sensitivity and specificity compared to other methods, and precision (batch-to-batch, inter-assay, intra-assay), and linearity.

Here's a breakdown of the acceptance criteria (inferred from the studies' findings) and the reported device performance:

Table of Acceptance Criteria and Reported Device Performance

Performance Metric	Acceptance Criteria (Inferred)	Reported Device Performance
Clinical Sensitivity for Microscopic Polyangiitis (MP)	Sufficiently high to aid diagnosis (e.g., lower bound of 95% CI > a clinically relevant threshold).	47.1% (95% CI: 33.1-61.0%) for MP.
Clinical Specificity for Healthy Normals	Very high (e.g., lower bound of 95% CI > 95%).	100% (95% CI: 97.5-100%) for Healthy Normals.
Clinical Specificity for SLE	Very high (e.g., lower bound of 95% CI > 90%).	97.1% (95% CI: 91.3-100%) for SLE.
Clinical Specificity for RA	Very high (e.g., lower bound of 95% CI > 95%).	100% (95% CI: 82.7-100%) for RA.
Relative Sensitivity vs. P-ANCA IFA	High degree of agreement (e.g., >80% with acceptable CI).	84.6% (95% CI: 70.5 - 98.8 %) against P-ANCA IFA.
Relative Specificity vs. P-ANCA IFA	High degree of agreement (e.g., >90% with acceptable CI).	94.8% (95% CI: 91.7 - 97.9 %) against P-ANCA IFA.
Relative Accuracy vs. P-ANCA IFA	High degree of agreement (e.g., >90% with acceptable CI).	93.7% (95% CI: 90.5 - 96.8 %) against P-ANCA IFA.
Relative Sensitivity vs. Alternate ELISA	Very high degree of agreement (e.g., >95% with acceptable CI).	96.0% (95% CI: 89.2 - 100 %) against an Alternate ELISA.
Relative Specificity vs. Alternate ELISA	Very high degree of agreement (e.g., >95% with acceptable CI).	98.8% (95% CI: 96.5 - 100 %) against an Alternate ELISA.
Relative Accuracy vs. Alternate ELISA	Very high degree of agreement (e.g., >95% with acceptable CI).	97.7% (95% CI: 95.0 - 100 %) against an Alternate ELISA.
Batch-to-batch CV %	Acceptable variability (e.g., <20-30% for lower concentrations, <15% for higher concentrations, depending on assay complexity).	Ranged from 5.5% to 26.0%. Highest for Sample 1 (23 units) at 26.0%.
Inter-assay CV %	Acceptable variability (e.g., <20% for lower concentrations, <10-15% for higher concentrations).	Ranged from 13.5% to 19.8%.
Intra-assay CV %	Acceptable variability (e.g., <15% for lower concentrations, <10% for higher concentrations).	15.6% for a sample of 49 units.
Linearity (r value)	Strong linear correlation (e.g., r > 0.9).	All 6 positive sera showed strong linear correlation with r values ranging from 0.893 to 0.996.

Sample sizes used for the test set and data provenance
- Clinical Sensitivity and Specificity Study (Table 1):
  - Test Set Sample Size: 364 frozen retrospective sera.
  - Data Provenance: Retrospective sera. Country of origin is not specified but given the submitter is from Sweden, it is likely based in Europe or an international panel.
- Comparison to P-ANCA IFA (Table 2):
  - Test Set Sample Size: 245 sera.
  - Data Provenance: Not explicitly stated as retrospective or prospective, but clinical characterization in other tables suggests a retrospective collection. Country of origin not specified.
- Comparison to Alternate ELISA (Table 3):
  - Test Set Sample Size: 129 frozen retrospective sera.
  - Data Provenance: Retrospective sera. Country of origin not specified.
Number of experts used to establish the ground truth for the test set and qualifications of those experts
- This information is not provided in the submission. The classification of patient groups (e.g., Microscopic Polyangiitis, Wegener's Granulomatosis, Systemic Lupus Erythematosus, Rheumatoid Arthritis, Anti-GBM nephritis, Healthy Normals) implies clinical diagnosis by medical professionals, but the number or specific qualifications of these "experts" (e.g., rheumatologists, nephrologists, pathologists) who established the ground truth are not detailed.
Adjudication method for the test set
- This information is not provided in the submission. The ground truth seems to be based on pre-existing clinical characterization of the serum samples, but how these clinical diagnoses were adjudicated is not described.
Multi-reader multi-case (MRMC) comparative effectiveness study, effect size
- No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not done. This device is an in vitro diagnostic (IVD) test kit (ELISA), not an AI-powered diagnostic imaging tool or a system designed to assist human readers in interpretation where an MRMC study would be applicable. The performance is assessed on the test's ability to detect an analyte directly.
Standalone (algorithm only without human-in-the-loop performance) study
- Yes, the studies presented are effectively standalone performance studies for the device. The ELISA kit generates quantitative results (absorbance/units) that are interpreted against a cut-off (e.g., >20 units for positive) directly by the user, without a human "in the loop" for interpretation of the primary signal beyond reading the instrument output and applying the defined interpretation criteria. The device's output is the result.
The type of ground truth used
- The ground truth for the clinical sensitivity and specificity study (Table 1) was based on clinical characterization of patient groups (e.g., diagnosed cases of microscopic polyangiitis, healthy normals, other autoimmune diseases).
- For the comparative studies (Tables 2 & 3), the ground truth was the result from a predicate/comparative method:
  - P-ANCA IFA (for Table 2).
  - An alternate commercial MPO ANCA ELISA (for Table 3).
Sample size for the training set
- This information is not provided in the document. The document describes the performance of the final device, but not its development process including how training sets (if any were used for assay development/optimization, calibration curve establishment) were utilized.
How the ground truth for the training set was established
- As the sample size and details of a training set are not provided, how its ground truth was established is also not described. For an ELISA kit, "training" typically refers to the optimization of reagents, concentrations, and establishment of cut-off values and calibrator curves, often using well-characterized positive and negative control samples. However, the specifics of this process are not detailed in this submission.

Summary

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K974166

Summary of Safety and Effectiveness Information MPO ANCA Test Kit

FEB 1 7 1998

Wieslab AB Ideon Research Park S-223 70 Lund Sweden Contact person: Dr. Jorgen Wieslander Telephone: 46-46-182840 Date of preparation: Jan 19, 1998

Description of Device: The Wielisa MPO ANCA Test Kit is an enzyme-linked ll. immunosorbent assay (ELISA) for the detection and semi-quantitation of IgG antibodies to myeloperoxidase (MPO) in human sera. The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of microscopic polyangiitis. FOR IN VITRO DIAGNOSTIC USE.

The wells of the microtiter strips are coated with purified myeloperoxidase. During the first incubation, specific antibodies in diluted serum, will bind to the antigen coating.

Predicate Device

The MPO ANCA test is substantially equivalent to the Immunoscan MPO ANCA ELISA Kit . Equivalence is demonstrated by the following comparative results:

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Table 1. Clinical Sensitivity and Specificity. A total of 364 frozen retrospective sera with clinical characterization were assayed. The following table summarizes the results.

Control andDisease groups	Totalnumber	Negative<10 units	Equivocal10-20 units	Positive>20 units
Healthy Normals:	120	120	0	0
WG:	70	57	4	9
MP:	55	27	4	24
SLE:	40	33	6	1
RA:	17	17	0	0
Anti-GBM nephritis:	62	34	11	17

MP = microscopic polyangiitis GBM = glomerular basement membrane WG = Wegener's granulomatosis, SLE = systemic lupus erythematosus RA = rheumatoid arthritis

Clinical Sensitivity (Equivocal samples excluded from calculations)

WG = 9/66 = 13.6%	95% confidence interval = 5.2-22.1%
MP = 24/51 = 47.1%	95% confidence interval = 33.1-61.0%
GBM = 17/51 = 33.3%	95% confidence interval = 20.1-46.5%

Clinical Specificity (Equivocal samples excluded from calculations)

SLE	= 33/34 = 97.1%	95% confidence interval = 91.3-100%
RA	= 17/17 = 100%	*95% confidence interval = 82.7-100%
Normals	= 120/120 = 100%	*95% confidence interval = 97.5-100%

The 95% confidence intervals were calculated using the normal method. *The 95% confidence intervals were calculated assuming one false positive.

ﻤ

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Table 2 A total of 245 sera were assayed on the Wielisa MPO ANCA Elisa and IFA. The following table summarizes the relative sensitivity and specificity.

Relative Sensitivity and Specificity of the Wielisa MPO ANCA Kit Compared to P-ANCA IFA .

		Wielisa MPO ANCA
		Positive	Equivocal	Negative	Total
P-ANCAIFA	Positive	22	0	4	26
P-ANCAIFA	Negative	11	8	200	219
	Total	33	8	204	245

Sera falling in the equivocal range were excluded from the following calculations

			95% Confidence Interval
Relative Sensitivity	= 22/26	= 84.6 %	70.5 - 98.8 %
Relative Specificity	= 200/211	= 94.8 %	91.7 - 97.9 %
Relative Accuracy	= 222/237	= 93.7 %	90.5 - 96.8 %

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Table 3 A total of 129 frozen retrospective sera were assayed by the Wielisa MPO ANCA ELISA and by an alternate commercial ELISA. The following table summarizes the relative sensitivity and specificity of the assay.

Relative Sensitivity and Specificity of the Wielisa MPO Kit Compared to an Alternate ELISA

MPO Wielisa

	Positive	Equivocal	Negative	Total
Positive	42	0	2*	44
AlternateELISA	Equivocal	1	0	19	20
Negative	0	0	65	65
Total	43	0	86	129
			95% Confidence Interval


	Relative SensitivityRelative SpecificityRelative Accuracy		= 42/44 = 96.0 %= 84/85 = 98.8 %= 126/129 = 97.7 %	89.2 - 100 %96.5 - 100 %95.0 - 100 %

Sera falling in the equivocal range were considered to be negative.

Both samples were from normal healthy patients.

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Table 4. Batch to batch variation.

Batch to batch variation was determined by testing seven different samples in duplicate. Results were obtained for four to six different batches.

Sample	Mean value	SD	CV %
1	23 units	6.0	26.0
2	73 units	4.0	5.5
3	149 units	28.2	18.9
4	20 units	2.8	14
5	21 units	2.5	12
6	20 units	3.8	19
7	23 units	1.4	6

Table 5. Inter-assay precision.

Inter-assay precision was determined by testing two different samples in duplicate. Results were obtained for six different runs. and the same of the same of the same of the same of the seat of the seat of the seat the seat the seat and

Sample	Mean value	SD	CV %
1	63 units	8.5	13.5
2	169 units	33.5	19.8

Table 6. Intra-assay precision.

Intra-assay precision was determined by testing one sample in 80 wells.
Sample	Mean value	SD	CV %
	49 units	.O	15.6

Table 7. Linearity

The values were determined for serial two-fold dilutions of six positive sera. The values were compared to log2 of dilution by standard linear regression. The data in Table 7 indicates that the assay has a linear relationship with serum dilution.

Serum	Neat	1:2	1:4	1:8	1:16	1:32	1:64	r
1	163	કર્	41	20	00	2		0.927
2	74	રર	39	18	7			0.996
3	146	83	રે રેણે રહ્યા છે. આ ગામનાં પ્રાથમિક શાળા, આંગણવાડી તેમ જ દૂધની ડેરી જેવી સવલતો પ્રાપ્ય થયેલી છે. આ ગામનાં પ્રાથમિક શાળા, પંચાયતઘર, આંગણવાડી તેમ જ દૂધની ડેરી જેવી સવલતો પ્રાપ	26	12	ব		0.951
4	258	162	112	રેર	34	19	8	0.943
ર	310	140	74	40	20	d		0.893
ર	34	23	13	7				0.989

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Image /page/5/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized caduceus symbol, which is a staff with two snakes coiled around it, and the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged in a circular pattern around the symbol. The caduceus is black, and the text is also black. The logo is simple and recognizable, and it is used to represent the U.S. Department of Health & Human Services.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

WEISLAB AB William L. Boteler c/o IMMUNO PROBE, INC. 1306 Bailes Lane, Suite F Frederick, MD 21701

FEB 17 1998

Re : K974166 Trade Name: Wielisa MPO ANCA Test Kit Regulatory Class: II Product Code: MOB 82 Dated: January 19, 1998 Received: January 20, 1998

Dear Mr. Boteler:

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 Regulations, 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 regulation (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 In addition, FDA may publish further regulatory action. announcements concerning your device in the Federal Register. Please note: 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 regulations.

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Page 2

Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at (770)488-7655.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a leqally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll free number (800) 638-2041 or at (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html"

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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Page 1 of 1

K974166 510(k) Number: Not known

Device Name: Wielisa MPO ANCA Test Kit

Indications For Use: Wielisa MPO ANCA Test Kit. An Enzyme Linked Immunosorbent Assay (ELISA) for the detection and semi-quantitation of IgG antibodies in human serum to MPO (Myeloperoxidase). The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of Microscopic polyangiitis.

Peter E. Maxon
(Division Sign Off)

Division of Clinical Laboratory De 510(k) Number

PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED) xt 「やっしりロア」

Concurrence of CDRH, Office of Device Evaluation (ODE) Prescription Use V OR Over-The Counter Use (Optional Format 1-2-96) (Per 21 CFR 801.109)

Regulation Number and Section

§ 866.5660 Multiple autoantibodies immunological test system.

(a)
Identification. A multiple autoantibodies immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoantibodies (antibodies produced against the body's own tissues) in serum and other body fluids. Measurement of multiple autoantibodies aids in the diagnosis of autoimmune disorders (disease produced when the body's own tissues are injured by autoantibodies).(b)
Classification. Class II (performance standards).