Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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Stability assessment of serum tumour markers: Calcitonin, chromogranin A, thyroglobulin and anti-thyroglobulin antibodies.

Author(s): Thirkettle S, Blaszczyk P, Evans R, Wheatley M, Abbas M, Russell J, Monaghan PJ

Publication: Ann Clin Biochem, 2023, Vol. 60, Page 212-216

PubMed ID: 36867512 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study compared levels of calcitonin, chromogranin A, thyroglobulin and anti-thyroglobulin antibodies in serum before and after storage at room temperature, 4°C and -20°C for 1, 3 5 and 7 days. Levels of calcitonin were also compared in serum specimens stored for up to 2 h at room temperature. Surplus serum from blood collected in Starstedt gel tubes that was centrifuged at 3000 g for 4 min was pooled (diagnosis and the number of patients were not specified). Serum pools with different baseline levels of calcitonin (101,138 and 12,267 ng/L.), chromogranin A (25, 75, 160 and 26,200 ng/mL), thyroglobulin (21,135 and 27,314 ng/mL) and anti-thyroglobulin antibodies (196, 607 and 2,147 IU/mL) were aliquoted and frozen at -80°C  immediately and after 1, 3, 5 and 7 days at room temperature, 4°C  and -20°C . To further investigate the stability of calcitonin, three serum pools were stored at room temperature and aliquots were frozen every 15 min for 2 h. Levels of calcitonin, thyroglobulin and anti-thyroglobulin antibodies were quantified using a Siemens Immulite 2000 analyzer and chromogranin A levels were assayed using a Thermo-Fisher Scientific Kryptor Compact analyzer. Stable levels was defined as remaining within the measurement uncertainty of the assay, which was 8.2% for calcitonin, 6.9% for chromogranin A, 6.9% for thyroglobulin and 16.4% for anti-thyroglobulin antibodies.

   Summary of Findings:

   Serum calcitonin levels declined progressively with specimen storage at room temperature or 4°C, with losses exceeding the measurement uncertainty first observed when specimens were stored for 1 day at room temperature (approximately 20%) or for 3 days at 4°C (approximately 15%). Further analysis showed that serum calcitonin levels were only stable for 60 min at room temperature. Serum chromogranin A levels declined by more than the measurement uncertainty when specimens were stored at room temperature for 3 days (7.5%) or 7 days at 4 (approximately 10%).  Serum calcitonin and chromogranin A were stable (within the measurement uncertainty) for at least 7 days when stored at -20°C  and thyroglobulin and anti-thyroglobulin antibody concentrations were stable for at least 7 days at all three temperatures investigated (room temperature, 4°C, -20°C).

   Biospecimens

   • Bodily Fluid - Serum

   Preservative Types

   • Frozen

   Diagnoses:

   • Not specified

   Platform:

   Analyte	Technology Platform
   Peptide	Clinical chemistry/auto analyzer
   Protein	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage duration	0 days 1 day 3 days 5 days 7 days
   Storage	Storage temperature	Room temperature 4℃ -20℃
   Storage	Time at room temperature	0 min 15 min 30 min 45 min 60 min 75 min 90 min 105 min 120 min

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