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The VB12 method is an in vitro diagnostic test for the quantitative measurement of Vitamin B12 (B12) in human serum and plasma on the Dimension® EXL™ with LM integrated chemistry system. Measurements of Vitamin B12 may be used in the diagnosis of vitamin B12 deficiency.

The LOCI ANEMIA CAL is an in vitro diagnostic product for the calibration of the LOCI FOLA and LOCI VB12 assays on the Dimension® EXL™ with LM integrated chemistry system.

The vitamin B12 method is a homogeneous, competitive chemiluminescent immunoassay based on LOCI® technology. LOCI® reagents include two synthetic bead reagents and biotinylated intrinsic factor (IF). The first bead reagent (Chemibead) is coated with a B12 derivative and contains a chemiluminescent dve. The second bead reagent (Sensibead) is coated with streptavidin and contains photosensitive dve. The patient sample is pretreated with sodium hydroxide (NaOH) and dithioerythritol (DTE) to release the serum B12 from its carrier proteins. Potassium cyanide (KCN) is added to convert all the forms of B12 into a single, cyanocobalamin form, and dicyanocobinamide is added to keep the B12 from rebinding with the carrier proteins. After the sample pretreatment, the biotinylated IF and chemibead reagents are added sequentially to the reaction vessel. Vitamin B12 from the sample competes with the B12-chemibead for a limited amount of biotinylated IF. Sensibead reagent is then added and binds to the biotin to form bead pair immunocomplexes. Illumination of the complex at 680 nm generates singlet oxygen from the Sensibeads which diffuses to the Chemibeads triggering a chemiluminescent reaction. The resulting signal is measured at 612 nm and is an inverse function of the concentration of vitamin B12 in the sample.

LOCI ANEMIA CAL is a multi-analyte liquid, frozen product containing Folate and Vitamin B12. All levels are prepared in a bovine serum albumin base. The kit consists of ten vials, two each of five levels containing 2 mL per vial.

The provided 510(k) summary focuses on establishing substantial equivalence for an in vitro diagnostic (IVD) device, specifically the LOCI Vitamin B12 Flex® reagent cartridge and the LOCI Anemia Calibrator, to predicate devices. This type of filing differs from those for AI/ML-enabled devices, which often involve comparative effectiveness studies with human readers.

As a result, the information required for a typical AI/ML-driven device's acceptance criteria and study design (such as sample size for test sets, data provenance, number of experts for ground truth, adjudication methods, MRMC studies, standalone performance metrics, training set details) is not present in this document. The study described here is primarily a method comparison and reproducibility study for an IVD assay, not an AI/ML algorithm that predicts or interprets clinical data for human-in-the-loop use.

However, I can extract the acceptance criteria and reported performance relevant to this IVD device's analytical validation.

Acceptance Criteria and Reported Device Performance (Analytical Validation)

Since this is an IVD device submission establishing substantial equivalence to a predicate, the "acceptance criteria" are implicitly tied to demonstrating comparable analytical performance to the predicate device and meeting analytical precision expectations.

Study Details (as inferable from the document):

1. Sample size used for the test set and the data provenance:

   • Reproducibility Study: Not explicitly stated as a "test set" in the AI/ML sense, but for the precision study, multiple runs over 20 days were performed for each material (3 Bio-Rad controls, 4 serum/plasma pools). Each test level was analyzed twice per day for 20 days.
   • Sample Type Equivalency Study: 78 matched serum, lithium heparin plasma, sodium heparin, and EDTA plasma samples. 71 were native, 6 spiked, 1 diluted. Data provenance is not specified (e.g., country of origin, retrospective/prospective).
   • Method Comparison Study: 166 native human serum samples. These ranged from 60 - 1966 pg/mL (predicate) and 86 - 1901 pg/mL (new device). 35 samples were positive for Intrinsic Factor Blocking Antibody (IFBA). Data provenance is not specified.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. For IVD devices, "ground truth" typically refers to the reference method or assigned values, not expert interpretation of images or clinical scenarios. In the method comparison, the predicate device's measurements served as a reference for comparison. Calibrator values were assigned from a master pool with traceability to USP Grade Vitamin B12.

3. Adjudication method (e.g., 2+1, 3+1, none) for the test set: Not applicable, as this is an analytical performance study for an IVD, not a diagnostic interpretation study.

4. 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: Not applicable. This submission is for an IVD assay, not an AI/ML-enabled diagnostic imaging or clinical decision support system that involves human readers.

5. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: The studies described assess the standalone analytical performance of the IVD assay without human interpretation of results beyond standard laboratory practices.

6. The type of ground truth used:

   • For the method comparison, the predicate device's measurements (Dimension Vista® VB12 method, K121994) served as the comparative reference.
   • For the calibrator, values are assigned from a master pool which has traceability to USP Grade Vitamin B12.
   • For precision, the established analytical performance characteristics for laboratory controls and serum/plasma pools serve as benchmarks.

7. The sample size for the training set: Not applicable. This is an IVD assay, not an AI/ML device requiring a training set in that context. The device's calibration involves specific calibrator materials with assigned values.

8. How the ground truth for the training set was established: Not applicable. The "ground truth" for the IVD's calibration is established via a master pool traceable to USP Grade Vitamin B12.

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