Evaluation of plasma ACTH stability using the Roche Elecsys immunoassay.
Author(s): Nandakumar V, Paul Theobald J, Algeciras-Schimnich A
Publication: Clin Biochem, 2020, Vol. , Page
PubMed ID: 32315613 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to compare adrenocorticotropic hormone (ACTH) levels in plasma after different durations of pre-centrifugation and post-centrifugation storage. The effects of not prechilling tubes and centrifuging at room temperature rather than 4°C on ACTH levels was also investigated.
Conclusion of Paper
ACTH levels declined progressively with storage of plasma at room temperature or 4°C with significant declines first observed after 24 h at room temperature and 12h at 4°C. Storage temperature did not significantly affect the decline. Pre-centrifugation storage of blood for up to 4 h and collection in unchilled tubes and centrifugation at room temperature did not significantly affect ACTH levels. The trends in ACTH stability were the same regardless of initial ACTH concentration.
Studies
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Study Purpose
The purpose of this study was to compare ACTH levels in plasma after different durations of pre-centrifugation and post-centrifugation storage. The effects of not prechilling tubes and centrifuging at room temperature rather than 4°C on ACTH levels was also investigated. Blood was obtained from 21 volunteers (diagnosis not specified), including those with high ACTH levels into K2EDTA tubes. Reference specimens were collected in prechilled tubes, transported to the laboratory on ice, and immediately centrifuged at 3200 rpm for 6 min at 4°C to obtain plasma. To investigate the effects of delayed centrifugation, specimens were centrifuged immediately after arrival in the laboratory or after 2 or 4 h at 4°C. To investigate the effects of pre-chilling tubes and refrigerated centrifugation, specimens were also collected and centrifuged at room temperature. Specimens were stored at -80°C until analysis. ACTH levels in plasma were measured immediately using a Roche Elecsys ACTH immunoassay on a Cobas 6000 and again after 4, 8, 12, 24, and 48 h at room temperature or 4°C.
Summary of Findings:
ACTH levels declined progressively with storage of plasma at room temperature or 4°C. During room temperature storage, average changes in ACTH were limited to <10% for the first 12 h but were -11.41% at 24 h and -18.35% at 48 h. ACTH levels were slightly more stable during 4°C storage with changes limited to <10% during the first 24 h but an average decline of 18.80% noted after 48 h. However, while significance was first observed after 24 h at room temperature (P=0.002), the decline was first significant after only 12h at 4°C (P=0.01). Plasma storage temperature did not significantly affect the decline. Pre-centrifugation storage for up to 4 h resulted in insignificant changes (approximately 2%) in the ACTH levels. Similarly, ACTH levels were comparable in blood that was collected in unchilled tubes and centrifuged at room temperature to those in blood collected in chilled tubes and centrifuged at 4°C. The trends in ACTH stability were the same regardless of initial ACTH concentration.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Peptide Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Acquisition Type of collection container/solution Pre-chilled tube
Tube not chilled
Biospecimen Aliquots and Components Centrifugation Centrifugation delays investigated
Multiple temperatures compared
Storage Storage conditions As blood
As plasma
Storage Storage duration 0 h
2 h
4 h
8 h
12 h
24 h
48 h
Storage Storage temperature 4°C
Room temperature