The QUIDEL CH50 Eq EIA intended to measure the total classical complement pathway activity in human serum, thereby allowing detection of a deficiency of one or more of the complement components C1 through C9. The QUIDEL CH50 Eq EIA is intended for laboratory and professional use.

Device Description

The QUIDEL CH50 Eq EIA provides a direct measure of the total classical complement activity in serum by quantifying the amount of TCC generated under standard conditions. The test uses a monoclonal antibody to a unique neoantigen to capture the TCC analyte. Since both the QUIDEL CH50 Eq EIA and the CH50 test rely on the generation of TCC and correlate, the QUIDEL CH50 Eq EIA's results are expressed in CH50 unit equivalents per milliliter.

AI/ML Overview

Here's a breakdown of the acceptance criteria and study information for the QUIDEL CH50 Eq EIA, based on the provided document:

Acceptance Criteria and Device Performance

Acceptance Criterion	Reported Device Performance	Comments
Overall Accuracy	Greater than 97%	Compared to the combined results from three hemolytic and one EIA-based assay.
Intra-assay precision	Good	Specific metrics (e.g., CV%) not provided, but stated as "good".
Inter-assay precision	Good	Specific metrics (e.g., CV%) not provided, but stated as "good".
Lot-to-lot consistency	Reproducibly manufacturable	Confirmed with "Lot-to-lot consistency analyses".
Interference	Potentially interfering substances were shown not to interfere with the test's performance.	No specific interfering substances or their concentrations cited.
Similarity to other commercially available tests	Similar in terms of features and intended use.	This is a qualitative assessment of substantial equivalence.
Stability/Shelf-life	Underway	Stability studies were ongoing at the time of submission.

Study Details

Sample Size used for the test set and data provenance:
- Sample Size: 226 patient samples.
- Data Provenance: Tested at a "major clinical reference laboratory in the United States." The samples were likely retrospective, though not explicitly stated as such.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The document does not specify the number of experts or their qualifications for establishing ground truth.
- The ground truth was established by "the combined results from three hemolytic and one EIA-based assay," rather than expert consensus on individual cases.
Adjudication method for the test set:
- Not applicable directly. Ground truth was established by comparing the QUIDEL CH50 Eq EIA results against a combination of reference assays, not by human adjudication of individual cases.
If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- No. This study is for an in-vitro diagnostic (IVD) device (an EIA assay) that directly measures an analyte. It does not involve human readers or AI in the interpretation of images or other subjective data, so an MRMC study is not relevant here.
If a standalone (i.e. algorithm only without human-in-the loop performance) was done:
- Yes, effectively. The "overall accuracy" of the QUIDEL CH50 Eq EIA "when compared to the combined results from three hemolytic and one EIA-based assay" demonstrates its standalone analytical performance. The device is intended for laboratory and professional use, implying a human operator performs the test and interprets the result, but the accuracy measurement itself is of the device's output.
The type of ground truth used:
- Comparative Reference Assays: The ground truth was established by the "combined results from three hemolytic and one EIA-based assay." These are established laboratory methods for measuring total classical complement activity.
The sample size for the training set:
- The document does not indicate a separate "training set" or its size. For an IVD assay like this, development typically involves optimizing reagents and protocols during analytical validation, rather than distinct training and test sets in the machine learning sense. The 226 patient samples can be considered the core clinical validation dataset.
How the ground truth for the training set was established:
- As no explicit training set is identified, this question is not directly applicable. If developmental work used samples, the ground truth would have likely been established through similar reference methods to those used for the test set, or through known healthy/diseased donor samples.

Summary

{0}------------------------------------------------

Jul 2 9 1998

1974111

SUMMARY OF SAFETY AND EFFECTIVENESS XI.

Product: OUIDEL CH50 Eq EIA

Manufacturer:

QUIDEL Corporation 10165 McKellar Court San Diego, CA 92121

Device Classification:

The device, QUIDEL CH50 Eq EIA, is similar to other FDA-cleared devices used to measure by immunochemical techniques complement components Clo, C1, C1, C1, C2, C4, C5, C6, C7, C8 and C9 in serum, other body fluids and tissues. Measurements of these proteins aid in the diagnosis of immunologic disorders, especially those associated with deficiencies of complement components (21 CFR 866.5240).

The Food and Drug Administration (FDA) published a final regulation in the Federal Register classifying Complement components immunological test system as Class II.

Intended Use:

The QUIDEL CH50 Eq EIA measures the total classical complement pathway activity in human serum, thereby allowing detection of a deficiency of one or more of the complement components C1 through C9. The CH50 Eq EIA is for laboratory and professional use.

Physiologic Basis for the Test:

The classical complement pathway is triggered by the binding of C1q component of C1 to immune complexes. This activation results in a cascade of enzymatic and non-enzymatic reactions, culminating in the formation of terminal complement complexes (TCC). Under standard conditions the level of TCC which can be generated in serum is a quantitative expression of the serum's total classical complement activity.

{1}------------------------------------------------

The traditional method for measuring the total classical complement activity in serum is the CH50 test. This test is a lytic assay which uses antibodysensitized sheep erythrocytes (EA) as the activator of the classical complement pathway and various dilutions of the test serum to determine the amount required to give 50% lysis. The percent hemolysis is determined spectrophotometrically. The CH50 test is an indirect measure of TCC, since the TCC themselves are directly responsible for the hemolysis which is measured.

Principle of the Test:

The OUIDEL CH50 Eq EIA for quantifying the total classical complement activity in human serum involves three basic procedures: (1) complement activation; (2) sample dilution; and, (3) assay for terminal complement complexes (TCC).

To activate the classical complement pathway, undiluted human serum samples and the Controls are added to microassay wells containing the complement Activator. During an incubation the classical pathway of complement is triggered and TCC are generated.

In the second step, the activated sera are diluted in microassay wells or test tubes and dispensed, together with the Standards, directly into a precoated microassay plate. The TCC present in the activated samples bind to the monoclonal antibodies coating the surface of the microassay wells.

In the third step, the TCC microassay plate is washed and loaded with an HRP-conjugate which will bind to the bound TCC. After washing, the TCC microplate is loaded with a chromogenic enzyme substrate. After incubation a reagent is added to stop color development. The absorbancies (A405 values) generated with the Controls, Standards and test specimens are measured spectrophotometrically. The color intensity of the reaction mixture is proportional to the concentration of TCC present and to CH50 units. Using the kit standard curve, assay results are expressed in CH50 unit equivalents per milliliter (CH50 U Eq/mL).

{2}------------------------------------------------

Safety and Effectiveness:

Numerous studies were undertaken to document the performance characteristics and the substantial equivalence of the QUIDEL CH50 Eq EIA to other commercially available products. These studies included the following:

The test was shown to be similar to other commercially available tests in terms of . features and intended use.
The test was shown to have good intra- and inter-assay precision. ●
Lot-to-lot consistency analyses showed the test to be reproducibly manufacturable. ●
Potentially interfering substances were shown not to interfere with the test's . performance.
Two hundred and twenty six (226) patient samples were tested at a major clinical . reference laboratory in the United States and evaluated by Receiver Operator Curve (ROC) Analysis. By this method the overall accuracy of the QUIDEL CH50 Eq EIA, when compared to the combined results from three hemolytic and one EIA-based assay, was greater than 97%.
. Stability studies are underway to establish the shelf-life of the product as its optimal storage and shipping conditions.

Conclusion:

These studies demonstrated the substantial equivalence of the QUIDEL CH50 Eq EIA to existing products already marketed. They further demonstrated the suitability of the product for laboratory and professional use. Such studies are a critical element in establishing the fundamental safety and effectiveness of the product and its appropriateness for commercial distribution.

{3}------------------------------------------------

Image /page/3/Picture/2 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES • USA" around the perimeter. Inside the circle is a stylized symbol that resembles a person embracing or supporting another person, represented by abstract shapes.

Jul 2 9 1998

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Mr. Edward J. McMullen Manager, Regulatory Compliance Ouidel Corporation 10165 McKellar Court San Diego, California 92121

Re : K974111/S1 Trade Name: QUIDEL CH50 Eq EIA Regulatory Class: II Product Code: DAE Dated: May 29, 1998 Received: June 2, 1998

Dear Mr. McMullen:

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 regulations 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 requirement, 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 regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Reqister. 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.

{4}------------------------------------------------

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 Putman

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 --------------------------------------------------------------------------------------------------------------------------------------------------------------------

{5}------------------------------------------------

Page _________________________________________________________________________________________________________________________________________________________________________

510(k) Number (if known):	K974111
---------------------------	---------

Device. Name:

QUIDEL CH50 Eq EIA

Indications for Use:

. ·

(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 Device
510(k) Number K974111

Prescription Use (Per 21 CFR 801.109)	OR	Over-The Counter Use
---------------------------------------	----	----------------------

(Optional Format 1-2-96)

Regulation Number and Section

§ 866.5240 Complement components immunological test system.

(a)
Identification. A complement components immunological test system is a device that consists of the reagents used to measure by immunochemical techniques complement components C1q , C1r , C1s , C2 , C3 , C4 , C5 , C6 , C7 , C8 , and C9 , in serum, other body fluids, and tissues. Complement is a group of serum proteins which destroy infectious agents. Measurements of these proteins aids in the diagnosis of immunologic disorders, especially those associated with deficiencies of complement components.(b)
Classification. Class II (performance standards).