Preparation and characterization of a human serum matrix suitable for quality control or reference materials

Characterisation and evaluation of external quality assessment scheme serum. Discussion paper from the European External Quality Assessment (EQA) Organisers Working Group C

This work reviews the procurement, specification and manufacture of serum for external quality assessment (EQA) and provides a checklist for scheme organisers. Guidance on the assessment of commutability and notes on the use of EQA materials to assess assay problems are provided. The importance of the appropriateness of materials in respect of scheme design and objectives, and the essential nature of a detailed specification prior to manufacture are emphasised.

Identification of interference affecting the gas-liquid chromatography analysis of valproic acid in quality control material

The matrix used to prepare control material for the Chemical Pathology Quality Assurance Programme Group of the Royal College of Pathologists of Australasia/Australian Association of Clinical Biochemists (RCPA/AACB) was investigated to identify a contaminant affecting the gas-liquid chromatography (GLC) analysis of valproic acid (VPA). The contaminant, not present in patients' sera, eluted with the octanoic acid internal standard in our GLC procedure. The compound was identified as octanoic acid. The source of this contamination could not be determined. The presence of endogenous octanoic acid in the RCPA/AACB quality control material precluded the use of octanoic acid as an internal standard.