(56 days)
For in vitro diagnostic use in the quantitative determination of cortisol in serum, plasma (EDTA and lithium heparin), and urine using the ADVIA Centaur® XP system.
Measurements of cortisol are used in the diagnosis and treatment of disorders of the adrenal gland.
The ADVIA Centaur Cortisol (COR) assay is a competitive immunoassay using direct chemiluminescent technology. Results are determined using a calibration curve that is generated specifically on each instrument by a 2-point calibration and a master curve with the reagent bar code. The ADVIA Centaur Cortisol (COR) assay is intended for use on the ADVIA Centaur family of analyzers. The ADVIA Centaur Calibrator E is a set of 2 level calibrators for the assay. Siemens recommends the use of commercially available quality control materials with at least two levels (low and high).
This document is focused on the ADVIA Centaur Cortisol (COR) assay, specifically the addition of plasma (EDTA and lithium heparin) as a sample claim. It seeks to demonstrate substantial equivalence to an existing device (K142723) which already had claims for serum and urine.
Acceptance Criteria and Reported Device Performance
The core of the study is to prove that the performance of the assay with the new plasma sample types is equivalent to its performance with serum (the established sample type). The primary acceptance criteria for this type of submission involve showing a strong correlation and minimal bias between the new sample type and the established one.
Table of Acceptance Criteria and Reported Device Performance:
| Performance Metric | Acceptance Criteria (Implicit from Industry Standards like CLSI EP09-A3) | Reported Device Performance (ADVIA Centaur Cortisol (COR) with new plasma claims vs. Serum) |
|---|---|---|
| Correlation Coefficient (r) | Typically, a correlation coefficient (r) close to 1.00 (e.g., >0.975 or >0.98 is often considered good for method comparison studies) indicating a strong linear relationship between the new and established methods. | Dipotassium EDTA Plasma vs. Serum: 1.00 |
| Lithium-Heparin Plasma vs. Serum: 1.00 | ||
| Slope (from Deming Regression) | A slope close to 1.00 (e.g., 0.95 to 1.05) indicating proportional agreement between the new and established methods. | Dipotassium EDTA Plasma vs. Serum: 0.95 |
| Lithium-Heparin Plasma vs. Serum: 0.96 | ||
| Intercept (from Deming Regression) | An intercept close to 0 (e.g., within a predefined range that is considered clinically insignificant) indicating fixed bias between the new and established methods. | Dipotassium EDTA Plasma vs. Serum: 0.24 µg/dL |
| Lithium-Heparin Plasma vs. Serum: 0.56 µg/dL | ||
| Bias from Interferents | Bias should be within acceptable limits for clinical significance (e.g., |
§ 862.1205 Cortisol (hydrocortisone and hydroxycorticosterone) test system.
(a)
Identification. A cortisol (hydrocortisone and hydroxycorticosterone) test system is a device intended to measure the cortisol hormones secreted by the adrenal gland in plasma and urine. Measurements of cortisol are used in the diagnosis and treatment of disorders of the adrenal gland.(b)
Classification. Class II.