(127 days)
The Diazyne 25-OH Vitamin D Assay is intended for use in clinical laboratories for the quantitative determination of 25hydroxywiamin D (25-OH-D) in human serum and plasma on automated chemistry analyzer. Measurement of 25-hydroxy wiamin D (25-OH-D) is for assessment of vitamin D sufficiency. For in vitro diagnostic use only.
The 25-0H Vitamin D Control Ser is intended for use as quality controls for Diazyne 25-0H Viamin D Assay Kit only. For in vitro diagnostic use only.
The Diazyme 25-OH Vitamin D Assay is a direct competitive colorimetric immunoassay for the quantitative determination of total 25-OH vitamin D in serum and plasma. The assay is based on the principle of alpha-complementation of the enzyme beta-galactosidase and the competition between an enzyme donor-25-OH Vitamin D conjugate, an anti-Vitamin D antibody and the 25-OH Vitamin D content of a serum sample. Samples with higher 25-OH Vitamin D concentrations produce higher beta-galactosidase activities and vice versa. A nitro-phenyl-0-galactoside derivative (NPG) is used as the enzyme substrate. The reaction's product has maximum absorbance at 415 nm. The 25-OH Vitamin D concentration of a specimen is proportional to the measured Bgalactosidase activity. Five calibration levels are needed for each run. Calibrators are treated exactly the same as patient samples.
The Diazyme 25-OH Vitamin D Control Set (2 levels) is intended for use with the Diazyme 25-OH Vitamin D Assay kit only. Controls are treated exactly the same as patient samples. The quality controls assist laboratory users in verification steps ensuring that the assay reagents are functioning correctly. Users are instructed to verify the calibration curve with the controls.
Here's a breakdown of the acceptance criteria and study information for the Diazyme 25-OH Vitamin D Assay, based on the provided text:
Acceptance Criteria and Device Performance
The provided 510(k) summary sets acceptance criteria implicitly through performance studies designed to meet CLSI (Clinical and Laboratory Standards Institute) guidelines and demonstrate substantial equivalence to a predicate device. While there isn't a single table explicitly titled "Acceptance Criteria," the performance studies detail the performance required for different analytical characteristics, and the reported results meet or exceed these implied criteria.
| Performance Study | Implied Acceptance Criteria (Based on CLSI guidelines and typical assay performance standards) | Reported Device Performance |
|---|---|---|
| Precision | Generally, total CV should be 0.95, slope near 1, intercept near 0). | - Correlation Coefficient (r): 0.984 (95% CI: 0.976 to 0.989) |
- Slope: 1.005 (95% CI: 0.969 to 1.041)
- Intercept: -0.21 (95% CI: -2.15 to 1.73) |
| Matrix Comparison | Acceptable agreement between different sample matrices (serum, plasma). Slopes near 1, intercepts near 0, and high R-squared values. | - Li-Heparin plasma vs. Serum: y = 0.9657 x - 0.6596, R² = 0.9736 - K3-EDTA plasma vs. Serum: y = 0.9948x - 0.7057, R² = 0.9866 |
| Reference Range | Establish a representative reference interval. | Observed range (2.5th to 97.5th percentile): 15.0 to 45.9 ng/mL. Median: 25.6 ng/mL. Lowest: 12.6 ng/mL. Highest: 51.4 ng/mL. |
Study Details
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Sample sizes used for the test set and the data provenance:
- Precision Study: 11 different precision levels (2 controls, 9 serum samples). Each specimen was measured 80 times (20 days, 3 reagent lots, 1 analyzer, 2 measurements per run). The origin of these samples (country of origin, retrospective/prospective) is not explicitly stated, but they are referred to as "serum controls" and "serum samples."
- Linearity Study: 11 levels prepared from a high serum sample and Vitamin D-depleted serum. Tested in triplicates. Data provenance not specified.
- LoB/LoD/LoQ Study: Not specified, but generally involves multiple measurements of blank, low-level, and higher-level samples. Data provenance not specified.
- Interference Study: Not specified how many replicates or individual samples per interferent were tested, but it involved adding substances to blood samples. Data provenance not specified.
- Cross-Reactivity Study: Not specified how many replicates or individual samples per metabolite were tested, but it involved adding these to "serum pool samples." Data provenance not specified.
- Method Comparison: 98 unaltered human serum samples. Data provenance not specified (country, retrospective/prospective).
- Matrix Comparison: 66 matched sets of serum, K3-EDTA plasma, and Li-Heparin plasma samples (including 7 spiked patient samples). Data provenance not specified.
- Reference Range Study: 157 apparently healthy individuals. Origin: 47 samples from Pennsylvania (Northern U.S.), 56 from Tennessee (Central U.S.), and 54 from Texas (Southern U.S.). All collected during Oct-Nov (fall season). These were prospective collections based on an IRB approved protocol where stated, and obtained from commercial sources/FDA Licensed Donor Center with informed consent.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
The device is an in vitro diagnostic (IVD) assay for measuring a biomarker. The "ground truth" for such devices is typically established through reference methods, certified calibrators, or comparison to legally marketed predicate devices, rather than expert human interpretation. In this case, comparison to theLIAISON® 25-OH Vitamin D TOTAL Assay(K112725, K071480) served as the primary reference for method comparison. The concentrations of Vitamin D in controls and calibrators are pre-assigned based on standardized methods.
Therefore, no human experts are directly involved in establishing the "ground truth" for the test set in the same way they would be for an imaging AI device. -
Adjudication method (e.g., 2+1, 3+1, none) for the test set:
Not applicable for this type of IVD chemical assay. Adjudication methods like 2+1 or 3+1 are used in studies where human readers interpret data (e.g., medical images), and disagreements need resolution. For quantitative assays, results are numerical and compared directly to reference values or predicate device results. -
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 is an IVD assay, not an AI imaging or diagnostic algorithm designed to assist human readers. Therefore, an MRMC study comparing human reader performance with and without AI assistance was not performed. -
If a standalone (i.e. algorithm only without human-in-the loop performance) was done:
Yes, the entire performance testing described (precision, linearity, LoB/LoD/LoQ, analytical specificity, method comparison, matrix comparison, reference range) represents the standalone performance of the Diazyme 25-OH Vitamin D Assay. It is an automated assay intended to provide a quantitative measurement without human interpretation of the primary result. -
The type of ground truth used (expert consensus, pathology, outcomes data, etc):
The "ground truth" concept for this device is primarily established through:- Reference Methods/Standardization: The assay provides quantitative values of 25-OH Vitamin D. The accuracy of these values is assessed by comparing them against certified calibrators, controls with known concentrations, and correlation with a legally marketed predicate device (LIAISON® 25-OH Vitamin D TOTAL Assay) which itself would have been validated against reference standards.
- Defined Concentrations: For studies like linearity, interference, and cross-reactivity, known concentrations of the analyte or interferent are spiked into samples to determine the device's response.
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The sample size for the training set:
Not applicable. This is a traditional in vitro diagnostic assay, not a machine learning or AI algorithm that requires a separate "training set." The assay's performance is determined by its chemical and enzymatic reactions, not by being "trained" on data. -
How the ground truth for the training set was established:
Not applicable, as no training set was used.
§ 862.1825 Vitamin D test system.
(a)
Identification. A vitamin D test system is a device intended for use in clinical laboratories for the quantitative determination of 25-hydroxyvitamin D (25-OH-D) and other hydroxylated metabolites of vitamin D in serum or plasma to be used in the assessment of vitamin D sufficiency.(b)
Classification. Class II (special controls). Vitamin D test systems must comply with the following special controls:(1) Labeling in conformance with 21 CFR 809.10 and
(2) Compliance with existing standards of the National Committee on Clinical Laboratory Standards.