1. Evaluation of plasma ACTH stability using the Roche Elecsys immunoassay
- Author
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Alicia Algeciras-Schimnich, Vijayalakshmi Nandakumar, and J. Paul Theobald
- Subjects
Immunoassay ,endocrine system ,030213 general clinical medicine ,Chromatography ,medicine.diagnostic_test ,Chemistry ,Clinical Biochemistry ,Sample processing ,Temperature ,Clinical Chemistry Tests ,General Medicine ,Plasma ,Adrenocorticotropic hormone ,030204 cardiovascular system & hematology ,03 medical and health sciences ,0302 clinical medicine ,Adrenocorticotropic Hormone ,Specimen collection ,medicine ,Humans ,In vitro degradation ,Centrifugation ,Sample collection - Abstract
Adrenocorticotropic hormone (ACTH) has been reported to be labile in blood due to proteolytic degradation and stringent procedures are followed to prevent in vitro degradation after sample collection.The purpose of this study was to examine the effect of time and temperature before and after separation of plasma from cells in the quantitation of plasma ACTH.Our current protocol includes sample collection in a pre-chilled tube, transport on ice and immediate centrifugation at 4 °C. These reference conditions were compared against sample processing in tubes and centrifuge set at room-temperature; using delayed centrifugation at 4 °C. ACTH stability was evaluated at ambient and refrigerated temperatures after collection and plasma separation using the reference protocol. Plasma samples were analyzed using the Roche Elecsys ACTH immunoassay.Quantification of ACTH was not impacted by the use of non-chilled tubes and centrifuge and up to a 4 h delay in separation of plasma from cells. Average percent differences in plasma ACTH concentration from time 0 was10% up to 12 h at ambient temperature. Refrigeration of plasma did not preserve ACTH stability at 12 h and longer storage resulted in significant ACTH degradation at both ambient and refrigerated temperatures.As supported by these data, previously recommended strict specimen collection and processing requirements are not necessary for measuring ACTH with the Roche Elecsys immunoassay.
- Published
- 2020