Objective: Ammonia is extremely unstable in blood specimens and has special requirements during transport, processing and storage. The aim of our study was to determine the stability of ammonia in EDTA K3 blood samples and to establish a protocol for sample handling. Methods: In this study, 36 healthy subjects and 47 inpatients diagnosed with type 2 diabetes mellitus were enrolled. Two peripheral blood samples were collected from healthy volunteers (Sample A1 and A2) and one peripheral blood sample was collected from the inpatients diagnosed with type 2 diabetes mellitus (Sample B). Sample A1 and B were transported in ice bath within 15 minutes of blood collection, centrifuged immediately and processed. The sample was re-centrifuged after 15 minutes and a second ammonia result was obtained. Sample A2 was transported at room temperature and stored between 2 and 4 hours, centrifuged and plasma ammonia measurement was performed. The sample was re-spun after 15 minutes and a fourth ammonia result was obtained. Results: In our study, in healthy group the difference between sample A2 and set point value (on ice, 15 minutes) is 25.08 µg/dl, showing an increase of 55.29%. After another 15 minutes, an increase of 82.02% was observed compared with the standard value. In diabetes mellitus group, after 30 minutes of blood collection, an increase of 11% over the set point value was observed. Conclusions: The blood specimen should be transported on ice to the laboratory and analyzed within 15 minutes of blood collection due to plasma ammonia spontaneously increase.
Introduction: The aim of this study was to determine the performance of the total testing process of complete blood count (CBC) on two different instruments in an emergency setting of a county hospital, and to design an appropriate internal quality control plan.Materials and method: Two models of Statistical Quality Control (SQC) were evaluated on Sysmex XT-1800i and Cell-Dyne Ruby: 3 levels of commercial blood every 8 hours (N=9) and an alternative model using 3 levels every 12 hours (N=6) as shift changes. Total Error (TE) was calculated using the formula: TE=Bias%+1.65xCV%; Sigma score was calculated using the formula: Sigma=[(TEa%–Bias%]/CV%. Values for coefficient of variation (CV%) and standard deviation (SD) were obtained from laboratory data and Bias% from proficiency testing. For the pre-analytical phase Sigma score was calculated, while for post-analytical phase the turnaround time (TAT) was assessed.Results: TE for all directly measured parameters, for both instruments, had lower values than Total Error allowable (TEa). CV% for almost all parameters had lower values than CV% derived from biological variation except for platelets (PLT) at low level on Sysmex XT-1800i and red blood cells (RBC) on Cell-Dyne Ruby. Sigma score ranged from as low as 2 to 10. Sigma score for pre-analytical phase was 4.2 and turnaround time was 36 minutes on average.Conclusions: Given the performances of the total testing process implemented for CBC in our laboratory, performing the internal control after every 50 samples/batch seems to fulfill both the Health Ministry Order (HMO) 1301/2007 and International Organization for Standardization ISO 15189:2013 recommendation. All quality instruments must work together to assure better patient results and every laboratory should design its own control plan that is appropriate for better quality achievement.
The aim of this study was to determine the rate of hemolyzed specimens sent to our laboratory for coagulation testing, assess the interference of hemolysis on coagulation for patients without anticoagulant therapy and to determine the reference intervals for PT, INR and aPTT for our laboratory in order to test our own limitations. Methods: To determine the hemolysis rate, 1,689 specimens were evaluated on a visual scale and with the hemolysis icterus lipemia (HYL) test on Architect c4000 instrument. 125 blood samples collected from subjects without anticoagulant therapy were hemolyzed in vitro and the PT, INR and aPTT results were compared before and after hemolysis.To determine reference intervals (RI) for PT, INR and aPTT in our population, 125 apparently healthy human subjects (according to CLSI C28-A2) were enrolled and tests were performed on Sysmex CS 2000i, using Siemens reagents. Results: Out of 1,689 samples, 9.46% were assessed as hemolyzed by the visual scale, while HYL test showed a 6.63% hemolysis rate. We found a shortening of 0.1s for PT, a diminution with 0.01 units for INR and a prolongation with 0.9s for aPTT from in vitro hemolyzed compared to non-lyzed samples. As to the reference intervals, we obtained in our laboratory versus reagents producer: for PT 9.8-13.9 s vs 9.8-12.1 s, and for aPTT 19.1-31.5s vs 23-31.9 s respectively; 28.38% more PT results and 13.44% more aPTT results were within range when we used local laboratory RI, compared to the manufacturer’s RI. Conclusions: The rate of hemolyzed coagulation samples in our laboratory is higher than the rate found in the literature. Nevertheless, for patients without anticoagulant therapy hemolyzed samples should be processed. Using our own reference interval leads to a significant reduced number of abnormal results.
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