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

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 (pCO2) and oxygen (pO2), hemoglobin oxygen saturation (sO2), 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. pCO2 was stable at ≤60 minutes at all temperatures. pO2 was stable for 45 minutes at 0-3.9°C, and sO2 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, pCO2, pO2, sO2, and lactate concentration in blood gas syringes.

Evaluation of the delta of immature platelet fraction as a predictive biomarker of inflammatory response after cardiac surgery.

AIMS: Cardiac surgery (CS) can induce an inflammatory response (IR) that is associated with poorer outcomes. Immature platelets are among the factors that may be associated with IR development. We aimed to evaluate whether immature platelet fraction (IPF) could be a predictive biomarker for IR and whether IPF could improve the prognosis assessment of IR for Acute Physiologic and Chronic Health Evaluation (APACHE II) and Sequential Organ Failure Assessment (SOFA) following CS. METHODS: Three-hundred and twenty-seven (327) patients who underwent CS were enrolled during the study period. IR was defined according to the need for vasopressor support (>48 hours). Perioperative variables and outcomes were registered in our database. IPF was measured immediately following CS and at 24 hours by Sysmex XN analyzer and the difference between both measurements (ΔIPF) was calculated. To assess the relationship between ΔIPF and IR, univariate and multivariate logistic regression were performed. To analyse the additive value of ΔIPF in APACHE II and SOFA scores in predicting IR, an area under the receiver operating characteristic (AUROC) curve was calculated. RESULTS: Among 327 patients included, 60 patients (18.3%) developed IR. Multivariate analysis showed ΔIPF was significantly associated with IR (OR: 1.26; 95% CI: 1.01 to 1.56; p=0.038). The combination of ΔIPF with scores improved the AUROC for IR prediction: 0.629 vs 0.728 (p=0.010) for APACHE II and 0.676 vs 0.715 (p=0.106) for SOFA. CONCLUSION: These findings suggested that ΔIPF may be a useful and low-cost biomarker for the early identification of patients at risk of IR development.

Reference intervals for a complete blood count on an automated haematology analyser Sysmex XN in healthy adults from the southern metropolitan area of Barcelona.

BACKGROUND: The examination of peripheral blood is routinely used as a basic test in daily medical practice. Reliable reference intervals are necessary to avoid misdiagnoses, and the establishment of those intervals is an important task for clinical laboratories.The aim of the present study was to establish the reference intervals for complete blood count (CBC) on a Sysmex XN haematology analyser in healthy adults from the southern metropolitan area of Barcelona (Spain). METHODS: A total of 213 apparently healthy adults who received a general health examination at Hospital Universitari de Bellvitge were recruited to this study. Blood samples collected in K3EDTA tubes were analysed on a Sysmex XN. Statistically relevant gender based partition was assessed, outliers removed, and the reference intervals calculated in concordance with Clinical and Laboratory Standards Institute (CLSI) EP28-A3C guidelines. RESULTS: The CBC reference intervals were established in 191 adults (64 men and 127 women) who fulfilled all of the inclusion criteria. Significant gender-dependent differences in red blood cells, haematocrit, haemoglobin and platelets were found. The rest of the CBC reference intervals were obtained from the overall data. CONCLUSIONS: We report CBC reference intervals established on a Sysmex XN analyser, a widely used automated analyser for which reference intervals were previously lacking in the literature. However, these reference intervals we recommend should be validated by individual laboratories for the local population as recommended by CLSI.