Technical note: Effect of delayed analysis of cooled lithium-heparinized whole blood on the stability of ionized calcium, ionized magnesium, sodium, potassium, chloride, glucose, and lactate in samples from dairy cows

摘要

The objectives of this study were to describe the stabilityof bovine whole-blood electrolytes, glucose, andlactate in samples collected in lithium heparin tubesand stored in thermoconductive modules immersed inice water. A total of 99 Jersey cows (40 first-parity, 18second-parity, and 41 third-parity or greater cows) froma commercial dairy farm in West Texas were enrolledbetween June and July 2018. Blood was collected fromthe jugular vein using a 60-mL polypropylene syringeand equally distributed into 5 spray-dried evacuatedlithium heparin tubes. Baseline samples were analyzedwithin 90 s of collection using a benchtop blood gasanalyzer. The remaining 4 tubes were stored in a thermoconductive,passive-temperature-regulating moduleinside a cooler with ice water. At 30 min and 2, 4,and 8 h post-collection, samples were removed from thetemperature-regulating module, gently inverted for 10s, and analyzed. Repeated-measures models were builtto evaluate the effect of time on the stability of ionizedCa (iCa), ionized Mg (iMg), Na, K, Cl, glucose,and lactate. Most of the analytes investigated remainedstable up to 8 h under ice water storage conditionsbefore analysis, including iCa, iMg, Cl, glucose, andlactate. However, Na and K were significantly affectedby delayed analysis: Na remained stable up to 4 hpost-collection, but K was not stable starting at 2 hpost-collection. The results of this study are useful inhelping future researchers and consultants to recognizeacceptable time delays between whole blood collectionand processing or analysis for electrolytes, glucose, andlactate.