Stability of pH, Blood Gas Partial Pressure, Hemoglobin Oxygen Saturation Fraction, and Lactate Concentration

Abstract

Background The storage temperature and time of blood gas samples collected in syringes constitute preanalytical variables that could affect blood gas or lactate concentration measurement results. We analyzed the effect of storage temperature and time delay on arterial or venous blood gas stability related to pH, partial pressure of carbon dioxide ( p CO 2 ) and oxygen ( p O 2 ), hemoglobin oxygen saturation ( s O 2 ), and lactate concentration. Methods In total, 1,200 arterial and venous blood sample syringes were analyzed within 10 minutes of collection. The samples were divided into different groups to determine parameter stability at 25, 4–8, and 0–3.9°C and at different storage times, 60, 45, 30, and 15 minutes. Independent sample groups were used for each analysis. Percentage deviations were calculated and compared with acceptance stability limits (1.65× coefficient of variation). Additionally, sample group sub analysis was performed to determine whether stability was concentration-dependent for each parameter. Results The pH was stable over all storage times at 4–8 and 0–3.9°C and up to 30 minutes at 25°C. p CO 2 was stable at ≤60 minutes at all temperatures. p O 2 was stable for 45 minutes at 0–3.9°C, and s O 2 was stable for 15 minutes at 25°C and for ≤60 minutes at 0–3.9°C. Lactate concentration was stable for 45 minutes at 0–3.9°C. Subanalysis showed that stability was concentration-dependent. Conclusions The strictest storage temperature and time criteria (0–3.9°C, 45 minutes) should be adopted for measuring pH, p CO 2 , p O 2 , s O 2 , and lactate concentration in blood gas syringes.

The Stability of Blood Gas Parameters Depends on Leukocyte Counts

“…Other studies have shown that se-vere leukocytosis led to rapid O2 consumption, which can cause false hypoxemia [3,4]. Therefore, the storage criteria recommended by Arbiol-Roca, et al [1] may not be sufficient to manage stability.…”

“…CHU Lille, Service de Biochimie Automatisée Protéines, Lille, France; 2 CHU Lille, Service d'Hormonologie, Métabolisme, Nutrition et Oncologie, Lille, France Dear Editor, Arbiol-Roca, et al [1] recently published an article titled "Stability of pH, blood gas partial pressure, hemoglobin oxygen saturation fraction, and lactate concentration" in the Annals of Laboratory Medicine. The authors reported that the stability of blood gas parameters primarily depends on the blood sample storage temperature and time.…”

“…Arbiol-Roca, et al . [ 1 ] recently published an article titled “Stability of pH, blood gas partial pressure, hemoglobin oxygen saturation fraction, and lactate concentration” in the Annals of Laboratory Medicine. The authors reported that the stability of blood gas parameters primarily depends on the blood sample storage temperature and time.…”

“…Therefore, the storage criteria recommended by Arbiol-Roca, et al . [ 1 ] may not be sufficient to manage stability.…”

“…In cases of low pH, in the absence of clinical signs and/or an obvious cause of a spurious pH value, we suggest checking leukocyte count. Spurious pH values can be caused by a delay (longer than 30 minutes) between sample collection and analysis, EDTA contamination, or inappropriate sample transport [ 1 , 5 ]. When the leukocyte count is >15×10 9 /L, we suggest using point-of-care testing (POCT) to measure blood gas parameters to avoid spurious results ( Fig.…”