A study of capped whole-blood samples from 40 participants compared sodium, potassium, chloride, and bicarbonate after zero, two, and four hours before centrifugation. Mean deviations for all analytes remained within biologically derived allowable limits.
Key findings
- MPDs were 1.5%, 4.2%, 1.9%, and 10.8% for sodium, potassium, chloride, and bicarbonate. Mean deviations at two hours were 0.2%, 0.1%, -0.4%, and -0.3%; at four hours, 0.3%, 2.1%, -0.7%, and -0.4%. All means were acceptable, but potassium rose over time.
Why this matters globally
Laboratories receiving remote samples need evidence-based transport windows. This work offers a stability-validation framework and may reduce unnecessary rejection, but each laboratory should verify performance with its own tubes, temperatures, transport conditions, and analyzers.
Thai researcher contribution
Mahidol University researchers conducted the specimen-handling and biologically based stability assessment, generating evidence directly relevant to Thai laboratory pre-analytical policies.
Limitations to consider
Only 40 participants were included, and mean deviations may conceal individual samples exceeding MPD. The abstract does not specify exact temperature range, tube type, analyzer, patient mix, or hemolysis frequency. Results should not be extrapolated to uncapped tubes, hotter conditions, or delays beyond four hours.