Abstract
Introduction: Transportation of whole blood samples is an important part of the preanalytical phase. In this study we evaluate the effect of storage duration and temperature on whole blood samples used for 15 biochemical routine tests.
Material and methods: Venous blood samples were obtained from 124 voluntary subjects (20 samples per analyte), and biochemical tests were analyzed at baseline, and after storage at 1, 3, and 5 hours (h) (plus at 24 h for some analytes) at 21°C and 30°C. Imprecision and bias was calculated from values at baseline at after storage, and compared to goals set by the laboratory. In order to assess the clinical importance of the storage conditions, results were compared with the allowable total error (TE%). To evaluate bias in relation to the analytical variation, we used plots with 90% confidence intervals (CI), calculated as the mean bias +/- 1,65* (√2* CV (%)-analytical) / √n).
Results: Red Blood Cell Count (RBC), Hemoglobin (HGB), Mean Corpuscular Volume (MCV), Thrombocyte Count (PLT), Monocytes (MONO), Neutrophils (NEUT), Eosinophils (EOS) and Sodium (NA) showed neither CV (%) or bias (%) above the goals set by the laboratory. Six analytes showed CV% above the CV (%)-goals; (Pregnancy-Associated Plasma Protein A (PAPP-A), Free-beta-human chorionic gonadotropin (βHCG), Potassium (K), White Blood Cell Count (WBC), Thyroid-Stimulating Hormone (TSH) and Parathyroid Hormone (PTH). Besides the high CV (%)’s, PAPP-A and βHCG showed biases that exceeded the bias goals during storage at 30 °C. PAPP-A increased with 6-9 % during 24 h, while βHCG increased from 7-10% at 3 h to 11-15% at 5 h to 50-65% at 24 h. When evaluating bias in relation to the analytical variation, PAPP-A and βHCG changed to a degree after 5 and 3 h at 30 °C that could not be explained by the analytical variation. Thus, for βHCG, 30 % of the measurements exceeded TE% at 5 h at 30 °C, while all measurements exceeded TE% at 24 h at 30 °C. Longer storage at 21 °C was associated with a significant increase in K of 0.1-10.3 % after 3 h and 2.4-10.6% after 5 h. When evaluating bias in relation to the analytical variation, the K increase after 3 h at 21 °C could not be explained by the analytical variation. 35% of the measurements exceeded TE% after 3 h at 21 °C, while 40% exceeded TE% after 5 h at 21 °C.
Conclusions: RBC, HGB, MCV, PLT, MONO, NEUT, EOS, NA and WBC are sufficiently stable in whole blood stored at 21 °C and 30 °C for up to 5 h. Storage temperature and time led to considerable increases in the concentration of especially βHCG and K that could affect clinical decision-making. Therefore, whole blood samples for βHCG should be analyzed within 3 h of collection, unless the temperature is kept at 21 °C. K should be analyzed before 3 h of collection when at stored at 21 º C.
Material and methods: Venous blood samples were obtained from 124 voluntary subjects (20 samples per analyte), and biochemical tests were analyzed at baseline, and after storage at 1, 3, and 5 hours (h) (plus at 24 h for some analytes) at 21°C and 30°C. Imprecision and bias was calculated from values at baseline at after storage, and compared to goals set by the laboratory. In order to assess the clinical importance of the storage conditions, results were compared with the allowable total error (TE%). To evaluate bias in relation to the analytical variation, we used plots with 90% confidence intervals (CI), calculated as the mean bias +/- 1,65* (√2* CV (%)-analytical) / √n).
Results: Red Blood Cell Count (RBC), Hemoglobin (HGB), Mean Corpuscular Volume (MCV), Thrombocyte Count (PLT), Monocytes (MONO), Neutrophils (NEUT), Eosinophils (EOS) and Sodium (NA) showed neither CV (%) or bias (%) above the goals set by the laboratory. Six analytes showed CV% above the CV (%)-goals; (Pregnancy-Associated Plasma Protein A (PAPP-A), Free-beta-human chorionic gonadotropin (βHCG), Potassium (K), White Blood Cell Count (WBC), Thyroid-Stimulating Hormone (TSH) and Parathyroid Hormone (PTH). Besides the high CV (%)’s, PAPP-A and βHCG showed biases that exceeded the bias goals during storage at 30 °C. PAPP-A increased with 6-9 % during 24 h, while βHCG increased from 7-10% at 3 h to 11-15% at 5 h to 50-65% at 24 h. When evaluating bias in relation to the analytical variation, PAPP-A and βHCG changed to a degree after 5 and 3 h at 30 °C that could not be explained by the analytical variation. Thus, for βHCG, 30 % of the measurements exceeded TE% at 5 h at 30 °C, while all measurements exceeded TE% at 24 h at 30 °C. Longer storage at 21 °C was associated with a significant increase in K of 0.1-10.3 % after 3 h and 2.4-10.6% after 5 h. When evaluating bias in relation to the analytical variation, the K increase after 3 h at 21 °C could not be explained by the analytical variation. 35% of the measurements exceeded TE% after 3 h at 21 °C, while 40% exceeded TE% after 5 h at 21 °C.
Conclusions: RBC, HGB, MCV, PLT, MONO, NEUT, EOS, NA and WBC are sufficiently stable in whole blood stored at 21 °C and 30 °C for up to 5 h. Storage temperature and time led to considerable increases in the concentration of especially βHCG and K that could affect clinical decision-making. Therefore, whole blood samples for βHCG should be analyzed within 3 h of collection, unless the temperature is kept at 21 °C. K should be analyzed before 3 h of collection when at stored at 21 º C.
| Originalsprog | Engelsk |
|---|---|
| Publikationsdato | 25 sep. 2021 |
| Status | Udgivet - 25 sep. 2021 |