Application of indicators for quality improvement in the coagulation laboratory.

Indicators are tools that measure work performance and serve as a guide to improve the quality of laboratories. Seven Indicators for quality improvement have been established in our coagulation laboratory. They are :- 1). percentage of pre-analytical problems, 2). personnel competency scores, 3). results of external quality assessment, 4). % coefficient of variation (CV) of control materials, 5). unit cost, 6). percentage of reports within determined time, and 7). percentage of customers who were satisfied. The percentage of preanalytical error gradually decreased from 1.8% in April 2001 to 0.8% in June 2001 as a result of co-operation between the coagulation laboratory and the wards. Since there is no system to check personnel competency at a national level in Thailand, we set up a program for testing personnel competency in our department by asking every technician to take a written and practical laboratory examination. The scores achieved by our personnel ranged from 40 to 90%. For those who achieved scores of lower than 70%, we limited their responsibilities and organized a training program for them. In order to check our laboratory's accuracy, we are enrolled in the WHO International External Quality Assessment Scheme (IEQAS) in Blood Coagulation and have been since 1987. The survey results indicated that most of our laboratory tests were within consensus including our homemade ELISA tests for protein C, protein S and vWF antigen. The percent CVs of control materials used for the internal daily control for every test were analyzed. They ranged from 2.3 for normal APTT to 11.4 for the low level of free protein S in plasma. The unit cost for each test was analyzed to determine the cost-effectiveness of the laboratory. We set the goal for the turn around time for emergency coagulation tests to be within an hour and the percentage of reports within this time was 91.6% in August 2001. The last indicator was the percentage of satisfied customers, which gave an indication of the quality of all Out Patient Department (OPD) services performed by our department. We sent 400 questionnaires to doctors, nurses and patients in OPD asking their opinion of both the technical services and the behavior of our technicians. The percentage satisfaction of our customers concerning services offered to OPD was lower than 50%. We plan to improve the last 2 indicators by expanding the space of the OPD/emergency laboratory and reorganizing the service system. All indicators mentioned above have helped to improve the quality of our laboratory greatly.

Hemostatic alterations in beta-thalassemia/hemoglobin E patients.

To search for evidence of coagulation activation ex vivo, the levels of human prothrombin fragment 1+2 (F1+2) were examined in 69 beta-thalassemia/Hb E patients. Levels of protein C inhibitor (PCI) and activated protein C - PCI (APC:PCI) complex were also determined in 9 of the above patients in conjunction with protein C (PC) antigen and activity, in an attempt to detect increased consumption of PC. In mean level of F1+2, there was a statistically significant difference between normal control and post-splenectomized patients (p < 0.05) but not between normal control and non-splenectomized patients (p > 0.05). The mean levels of PC activity and PC antigen in the patients were much lower than in normal controls. However, the mean levels of PCI and the mean level of APC:PCI complex in the patients were not significantly different from those in normal controls (p > 0.05). The high level of F1+2 in post-splenectomized patients found in this study agreed well with clinical and other laboratory findings. The normal level of PC inhibitor and APC:PCI complex found in this study provided no evidence of increased consumption of protein C in thalassemia patients.

Effect of different oral anticoagulant intensities on prothrombin fragment 1 + 2 in Thai patients with mechanical heart valve prostheses.

The minimal intensity of oral anticoagulant required for antithrombotic protection in patients with a mechanical heart valve is still debatable, and that of the Westerner may not be directly applied to Thai patients. Our preliminary clinical review suggested that International Normalized Ratio (INR) 2-3 might be enough but it needs further supporting evidence. Therefore, we studied the effect of different anticoagulant intensities, expressed as INR, on the in vivo coagulation activation by measuring prothrombin fragment 1 + 2 (F1 + 2) in 116 patients with mechanical heart valve replacements. The patients had received warfarin for not less than one month with different intensities. The mean +/- S.D. of F1 + 2 level in 30 normal controls was 0.7 +/- 0.17 nmol/L. After excluding two outliers, the maximum linear correlation between INR and F1 + 2 was -0.658 (p < 0.001) when only patients whose intensities were lower than INR3 were taken into account. Adding more data from the patients having higher intensities decreased the correlation coefficient. The patients were subsequently classified by INR values in the range INR 1.1-1.9, 2-3 and 3.1-4.2. The F1 + 2 in each group was 0.6 +/- 0.30, 0.28 +/- 0.13 and 0.24 +/- 0.13 nmol/L respectively. The F1 + 2 in the first group did not differ from normal (p = 0.119) but was higher than the others (p = 0.000). The latter two groups had no difference between them (p = 0.112). Hence, from the laboratory point of view, we did not see additional benefit in the reduction of thrombin activation by the anticoagulant intensities higher than the range INR 2-3. The evidence supported that this therapeutic range might be enough for Thai patients with mechanical heart valves.