Stable Plasma Sample Storage in Acetonitrile for Angiotensin and Aldosterone Analysis.

ABSTRACT

BACKGROUND: Angiotensin I, II (AI, AII) and aldosterone are unstable in plasma specimens at room temperature, making it difficult for collect samples for remote regions in centralized and collaborative studies. Here we introduce a stable storage method which do not require cold conditions.. METHODS: Acetonitrile was added to the plasma to 60%, and then the supernatants were kept at 4°C and room temperature for 0, 1, 2, 3, 10 and 30 days. AI, AII and aldosterone were extracted and analyzed by chemiluminescence immunoassays. RESULTS: AI, AII and aldosterone were well retained in the supernatant under this method. The intra- and inter-day CVs of this method were all below 10%. The levels of AI, AII and aldosterone by this method remained stable for 30 days at room temperature. CONCLUSION: Addition of 60% acetonitrile in the plasma provides a stable storage method for clinical AI, AII and aldosterone.