Storage of Serum or Whole Blood Samples? Effects of Time and Temperature on 22 Serum Analytes

Abstract

Information on the stability of serum analytes during storage of serum or whole blood samples is often incomplete and sometimes contradictory. Using a widely available analyser (Hitachi 737/Boehringer), we therefore determined the effects of storage time and temperature on the measured concentrations of the following serum analytes: sodium, potassium, calcium, chloride, inorganic phosphate, magnesium, creatinine, urea, uric acid, bilirubin, cholesterol, HDL-and LDL-cholesterol, triacylglycerols, creatine kinase, aspartate aminotransferase, alanine aminotransferase, -glutamyltransferase, alkaline phosphatase, -amylase, lactate dehydrogenase and cholinesterase.When separated serum was stored at + 9 °C for seven days, the mean changes in inorganic phosphate and lactate dehydrogenase exceeded significantly (p < 0.05 or 0.001, respectively) the maximum allowable inaccuracy according to the Guidelines of the German Federal Medical Council; all other quantities were sufficiently stable.In serum at room temperature, inorganic phosphate, uric acid, HDL-cholesterol and triacylglycerols increased continuously, whereas bilirubin, LDL-cholesterol, creatine kinase and aspartate aminotransferase decreased more than the guidelines permit during the storage period (p < 0.05 for aspartate aminotransferase, p < 0.001 for the other analytes mentioned).In whole blood stored for 7 days at + 9 °C, only the following serum analytes satisfied the stability requirements of the guidelines: calcium, urea, cholesterol, HDL-cholesterol, LDL-cholesterol, triacylglycerols, creatine kinase, -glutamyltransferase and cholinesterase. When stored at room temperature, only sodium, uric acid, bilirubin, cholesterol, triacylglycerols, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, -amylase and cholinesterase were still stable after 3 days.The data collected show that all quantities examined are sufficiently stable for four days in separated serum stored at + 9 °C.

Long‐term stability of serum components in the Janus Serum Bank

“…Earlier studies (18)(19)(20)(21) have addressed short-term stability at different temperatures (-20 ºC and up to +3 ºC) for different components in serum, but there are limited data for storage temperature of -25 °C and storage time exceeding more than a few years.…”

Does Prolonged Storage of Serum Samples alter the Lab Results?

“…12 Increased lactate concentration after 72 hours may also have interfered with the methodology. Creatinine increased by 71.4% after 72 hours and by 185% after 3 months (Graph 1), which was attributable to interference of pseudocreatinines as shown by Heins et al 13,14 Such massive increase cannot be explained just by hemoconcentration. Potassium concentration though showed increase after 24 hours, significant increase of 50% was seen only after 72 hours.…”

Stability of Lyophilized Human Serum for Use as Quality Control Material in Bhutan

“…From the statistical results using SPSS program, p values \0.050 were obtained for glucose, creatinine, ALT and total protein for the sample store at 2-8°C. There are many literatures describing the instability of the biological compounds in lyophilized and liquid serum stored at various temperatures [18][19][20][21]. Since we prepared our control material without additives and stabilizers for glucose and enzymes, the slight decrease in glucose levels could be due to degradation by microbial agents during the storage [19,20].…”

“…There are many literatures describing the instability of the biological compounds in lyophilized and liquid serum stored at various temperatures [18][19][20][21]. Since we prepared our control material without additives and stabilizers for glucose and enzymes, the slight decrease in glucose levels could be due to degradation by microbial agents during the storage [19,20]. Increase in creatinine may be attributed to the formation of pseudocreatinine in Jaffe's reaction [20].…”