ALPCO 25(OH) Vitamin D CLIA Kit - Fresh Versus Frozen Serum and Plasma Stability Study

This clinical study is designed to assess the analytical stability of 25-hydroxyvitamin D \[25(OH)D\] in human serum and plasma specimens under defined storage conditions using the ALPCO 25(OH) Vitamin D CLIA Kit, a competitive chemiluminescent immunoassay performed on the KleeYa automated platform.

The study consists of two cohorts. Cohort 1 evaluates long-term stability of 25(OH)D in human serum specimens following storage at ultra-low temperatures (-80°C). Approximately 30 donor-derived serum samples representing clinically relevant vitamin D levels (deficient, insufficient, and sufficient) will be tested at baseline and after storage for predefined time points up to six months. The objective of this cohort is to demonstrate equivalence between fresh and frozen specimens following a single freeze-thaw cycle.

Cohort 2 evaluates short-term stability of 25(OH)D in both serum and plasma specimens under multiple temperature conditions (2-8°C, 22°C, 37°C, and -80°C) over a defined period of up to 31 days. Approximately 10 donor-derived specimens will be tested at baseline and at predefined intervals to assess the impact of sample handling and storage conditions relevant to routine laboratory workflows.

Adult participants (≥22 years of age) will provide a single blood sample collected via standard venipuncture. Specimens will be processed, aliquoted, and tested according to protocol-defined procedures. The primary endpoint is the equivalence of 25(OH)D measurements between fresh and stored specimens. Data analysis will include descriptive and comparative statistical methods, including percent difference and mean bias, to evaluate stability across conditions.

This is a minimal-risk study involving no therapeutic intervention. Results are intended to support analytical performance claims, including specimen handling and storage conditions described in the assay Instructions for Use. No clinical benefit to participants is expected, and study results will not be used for medical decision-making.