IMMULITE® Vitamin B12 is a chemiluminescent assay for use with the IMMULITE® Automated Analyzer and designed for the quantitative detection of vitamin B12 in human serum or heparinized plasma. It is intended strictly for in vitro diagnostic use as an aid in clinical diagnosis and treatment of anemia.

Device Description

IMMULITE® Vitamin B12 is a clinical device for use with the IMMULITE® Automated Immunoassay Analyzer. IMMULITE® Vitamin B12 is a chemiluminescent assay for use with the IMMULITE® Automated Analyzer and designed for the quantitative detection of vitamin B12 in human serum or heparinized plasma.

AI/ML Overview

Here's an analysis of the provided text, focusing on the acceptance criteria and study details:

1. Table of Acceptance Criteria and Reported Device Performance

The text does not explicitly state pre-defined acceptance criteria for the comparative studies. Instead, it presents the results of method comparison studies and implies that these results were deemed acceptable for regulatory clearance. The "acceptance criteria" are implicitly the statistical measures of agreement shown in the linear regression analysis (slope, intercept, correlation coefficient).

Acceptance Criteria (Implied)	IMMULITE® vs. DPC SPNB Dualcount®	IMMULITE® vs. Bio-Rad Quantaphase II®
Linear Regression Slope	0.99	0.91
Linear Regression Intercept	19.1 pg/mL	19.5 pg/mL
Correlation Coefficient (r)	0.982	0.965
Mean Difference	(IMMULITE® mean = 385 pg/mL, SPNB mean = 371 pg/mL) - Not explicitly stated as a criterion, but means are provided.	(IMMULITE® mean = 396 pg/mL, Quantaphase II® mean = 412 pg/mL) - Not explicitly stated as a criterion, but means are provided.

2. Sample Size Used for the Test Set and Data Provenance

IMMULITE® vs. DPC SPNB Dualcount®:
- Sample Size: 98 patient serum samples.
- Data Provenance: Not explicitly stated, but the samples are referred to as "patient serum samples." It is likely retrospective, collected from a human population, but the specific country of origin or whether it was prospective is not mentioned.
IMMULITE® vs. Bio-Rad Quantaphase II®:
- Sample Size: 101 patient serum samples.
- Data Provenance: Not explicitly stated. Similar to the above, these are "patient serum samples," likely retrospective from a human population, with no specific country of origin or prospective/retrospective status mentioned.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

Not applicable. This device is an in vitro diagnostic (IVD) assay measuring a quantitative biomarker (Vitamin B12). The "ground truth" for the test set is established by the comparative reference methods (DPC's SPNB Dualcount® and Bio-Rad's Quantaphase II® B12 Radioassay), not by human expert interpretation.

4. Adjudication Method for the Test Set

Not applicable. As this is an IVD device measuring a biomarker, there is no human adjudication process for the test results. The comparison is between the quantitative values reported by the new device and the reference methods.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance

Not applicable. This is not an AI-assisted diagnostic device that involves human readers or interpretation of complex medical images/data. It is an automated in vitro diagnostic immunoassay for a biomarker.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, the studies presented are standalone performance studies of the IMMULITE® Vitamin B12 device against established reference methods. The device generates quantitative results independent of human interpretation for the measurement itself.

7. The Type of Ground Truth Used

The ground truth used for these studies is the quantitative measurement of Vitamin B12 by two previously cleared and commercially marketed reference immunoassay devices:

DPC's Solid Phase No Boil Dualcount® (K860815)
Bio-Rad's Quantaphase II® B12/Folate Radioassay (K933315)

This is a form of comparative reference standard ground truth.

8. The Sample Size for the Training Set

The document does not explicitly mention a "training set" in the context of machine learning or AI. For IVD devices, development typically involves internal validation and optimization studies (which could be considered analogous to a training phase in AI development, but using different methodologies). The document describes the "Description of Device" and "Technology Comparison," which outlines how the device performs measurements, implying the assay was developed and optimized prior to the comparative tests presented. However, specific numbers for an internal development or training sample size are not provided.

9. How the Ground Truth for the Training Set Was Established

Since a "training set" in the AI/ML sense is not explicitly discussed, the establishment of its "ground truth" is also not detailed. The ground truth for the performance evaluation (test set) was established by comparison to the two predicate devices. For assay development and optimization, the "ground truth" would typically involve highly characterized samples, gravimetric standards, or other established laboratory reference methods to ensure accurate measurement across the dynamic range.

Summary

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K971177

Diagnostic Products Corporation IMMULITE® Vitamin B12 Anril 28 1997

MAY 16 1997

510(k) Summary of Safety and Effectiveness

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR Part 807.92.

Name: Address:

Telephone Number: Facsimile Number:

Contact Person:

Date of Preparation:

Device Name: Trade:

Catalog Number:

Classification:

Manufacturer:

Establishment Registration #:

Substantially Equivalent Predicate Device:

Description of Device:

Intended Use of the Device:

Diagnostic Products Corporation 5700 West 96th Street Los Angeles, California 90045-5597

(213) 776-0180 (213) 776-0204

Edward M. Levine, Ph.D. Director of Clinical Affairs

April 28, 1997

IMMULITE® Vitamin B12 Reagent system for the determination of vitamin B12 in serum or heparinized plasma

LKVB1 (100 tests); LKVB5 (500 tests)

Class II device (862.1810, 75CDD)

Diagnostic Products Corporation 5700 West 96th Street Los Angeles, California 90045-5597

DPC's Registration # is 2017183

DPC's Solid Phase No Boil Dualcount® (K860815); Bio-Rad's Quantaphase II® B12/Folate Radioassay (K933315).

IMMULITE® Vitamin B12 is a clinical device for use with the IMMULITE® Automated Immunoassay Analyzer.

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Diagnostic Products Corporation IMMULITE® Vitamin B12 April 28, 1997

Summary and Explanation of the Test:

Vitamin B12 (cobalamin) and folate are nutrients essential to hematopoiesis. Megaloblastic anemia is almost always due to lack of one of these two vitamins. Vitamin B12 deficiency can also result in severe neurological impairment.

Circulating levels of vitamin B12 are usually a good index to tissue stores. That is, vitamin B12 levels as measured in serum or plasma by an optimized assay system are typically low in vitamin B12 deficiency, and normal or elevated otherwise. Exceptions to this rule can occur in those relatively uncommon situations where levels of vitamin B12 transport proteins are abnormal. Thus, low circulating vitamin B12 levels can occur in the absence of vitamin B12 deficiency where the level of transcobalamin I (a physiologically inactive transport protein) is low.

Conversely, vitamin B12 deficiency can occur in the presence of normal or even elevated plasma vitamin B12 levels where transcobalamin II levels are low or where levels of inactive vitamin B12 transport proteins are high, as in chronic myelogenous leukemia. (Circulating folate levels are usually normal or elevated in vitamin B12 deficiency, but red cell folate levels are frequently low in this condition.)

Vitamin B12 deficiency occurs only rarely as a result of dietary lack of this vitamin. More commonly, it results from impaired absorption, as in partial or total gastrectomy, or in pernicious anemia, a condition characterized by absence or near absence of intrinsic factor. Since roughly two thirds of all patients with pernicious anemia have blocking antibodies to intrinsic factor (IFbAb), while IFbAb are only very rarely encountered in other situations, IFbAb determinations represent a useful follow-up test for the differential diagnosis of vitamin B12 deficiency. (Circulating intrinsic factor antibodies are present in more than half of all pernicious anemia patients. Increased transport protein levels can occur, for example in chronic myelogenous leukemia.)

Common causes of high vitamin B12 levels include liver disease, myeloproliferative disease (with chronic myelogenous leukemia as a special case) and the use of multivitamin supplements.

Performance Equivalence - Technology Comparison:

IMMULITE® Vitamin B12 is a chemiluminescent immunoassay, DPC's SPNB Dualcount® is a radioassay. The technology in DPC's IMMULITE® Vitamin B12 is a unique combination of technologies employed in previously cleared and commercially marketed DPC products.

IMMULITE® Vitamin B12 is a chemiluminescent version of the classic method for vitamin B12 radioassay, involving a preliminary heat denaturation step. Vitamin B12 in the patient sample is released from carrier proteins by incubation at 100°C in the

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Diagnostic Products Corporation IMMULITE® Vitamin B12 April 28, 1997

Technology Comparison: (continued)

presence of dithiothreitol and potassium cyanide to inactivate intrinsic factor antibodies and even the most extreme levels of vitamin B12 transport proteins.

After the heat denaturation step, the treated patient sample and purified hog intrinsic factor are simultaneously introduced into an IMMULITE® Test Unit containing a polystyrene bead coated with a B12 analog, and incubated for approximately 30 minutes at 37°C with intermittent agitation. During this incubation, vitamin B12 in the treated sample competes with the B12 analog on the solid phase for a limited number of vitamin B12 binding sites on the purified intrinsic factor. (Endogenous vitamin B12 analogs do not interfere, because the binder is free of R-protein.) Alkaline phosphatase-labeled anti-hog intrinsic factor is introduced, and the Test Unit is incubated for another 30-minute cycle. The unbound enzyme conjugate is removed by a centrifugal wash.

Substrate is then added, and the Test Unit is incubated for a further 10 minutes. The chemiluminescent substrate, a phosphate ester of adamantyl dioxetane, undergoes hydrolysis in the presence of alkaline phosphatase to yield an unstable intermediate. The continuous production of this intermediate results in the sustained emission of light, thus improving precision by providing a window for multiple readings. The bound complex - and thus also the photon output, as measured by the luminometer - is inversely proportional to the concentration of vitamin B12 in the sample.

In DPC's SPNB Dualcount® procedure, simultaneous assay of vitamin B12 and folic acid is accomplished by means of a Master Tracer with two isotopes, cobalt 57 (700) and iodine 125 (151). which are easily separated by most dual-channel gamma counters. Vitamin B12 and folic acid in the patient sample are released from carrier proteins by incubation at an elevated pH, above 12. in the presence of dithiothreitol and potassium cvanide. This inactivates the intrinsic factor antibodies.

Purified hog intrinsic factor and folate binding protein are employed as the binders for vitamin B12 and folic acid, respectively. With the binders immobilized on microcrystalline cellulose particles, isolation of the bound fraction becomes a simple matter of centrifuging and decanting. Counts in the precipitate are then transformed by comparison with a calibration curve into vitamin B12 and folic acid concentrations.

The Quantaphase II B12 and Folate Radioassays are performed by combining a serum or plasma sample with vitamin B12 (*7Co) and/or folate (151) in a solution containing dithiothreitol (DTT) and cyanide. The mixture is boiled to inactivate endogenous binding proteins and to convert the various forms of vitamin B12 to cyanocobalamin. The reduced folate and its analogs are stabilized by DTT during the heating procedure which involves placing the patient sample and standards in a boiling water bath at 100°C and allowing the samples to incubate for a minimum of 20 minutes. The mixture is cooled and then combined with immobilized, affinity-purified porcine

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Diagnostic Products Corporation IMMULITE® Vitamin BI 2 April 28, 1997

Technology Comparison: (continued)

intrinsic factor and folate binding protein. This addition is then incubated for one hour at room temperature.

During incubation, the endogenous and labeled vitamins compete for the limited number of binding sites based on their relative concentrations. The reaction mixture is then centrifuged and decanted. Labeled and unlabeled vitamins binding to the immobilized binding proteins are concentrated at the bottom of the tube in the form of a pellet. The unbound vitamins in the supernatant are discarded and the radioactivity associated with the pellet is counted. Standard curves are prepared using vitamin B12 and folate standards in a human serum albumin base. The concentrations of the vitamin B12 and folate in the serum or plasma sample are determined from the standard curves.

Performance Equivalence - Method Comparison:

The IMMULITE® Vitamin B12 procedure was compared to DPC's SPNB Dualcount® on 98 patient serum samples, with vitamin B12 concentrations ranging from approximately 90 to 1,143 pg/mL.

385 pg/mL (IMMULITE® Vitamin B12) Means: 371 pg/mL (DPC's SPNB Dualcount®)

Linear regression analysis of vitamin B12 values vielded the following statistics:

(IMMULITE®) = 0.99 (SPNB) + 19.1 pg/mL r = 0.982

IMMULITE® Vitamin B12 procedure was also compared to Bio-Rad's The Quantaphase II® B12 Radioassay on 101 patient serum samples, with vitamin B12 concentrations ranging from approximately 102 to 1,218 pg/mL.

396 pg/mL (IMMULITE® Vitamin B12) Means: 412 pg/mL (Quantaphase II® B12)

Linear regression analysis of vitamin B12 values yielded the following statistics:

(IMMULITE®) = 0.91 (Quantaphase II®) + 19.5 pg/mL r = 0.965

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Diagnostic Products Corporation IMMULITE® Vitamin Bl 2
April 28, 1997

Conclusion:

The data presented in this summary of safety and effectiveness is the data the Food and Drug Administration used in granting DPC substantial equivalence for IMMULITE® Vitamin B12.

Edwardh. Surner

Edward M. Levine, Director of Clinical Affairs

4/8/97
Date

Date

Regulation Number and Section

§ 862.1810 Vitamin B

12 test system.(a)
Identification. A vitamin B12 test system is a device intended to measure vitamin B12 in serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of anemias of gastrointestinal malabsorption.(b)
Classification. Class II.