Determination of quality parameters of platelet concentrates at Kenyatta National Hospital's blood transfusion unit

Abstract

Platelet concentrates are increasingly being used as part of supportive therapy in the management of haematological malignancies. Platelet transfusion therapy is also indicated in thrombocytopenia due to various causes including all forms of bone marrow failure. Production of platelet concentrates is expensive and rigorous. They also deteroriate rapidly during storage and have a short shelf life.Therefore it is important to evaluate the quality of platelets concentrates transfused so as to prevent wastage,ensure efficacy and maximum benefit to the patient as well as to avoid exposing a patient to multiple transfusions. Efforts to formulate standards for platelet concentrates have resulted in minimum requirements being prescribed by American Association of Blood Banks (AABB).These have subsequently been adopted by Standards Committee of Kenya National Blood Transfusion Service (NBTS). These standards stipulate the methods and processes of platelet concentrate preparation, requirements for platelet counts,residual WBC content,volume and final pH.This study sought to find out if the platelet concentrates prepared Kenyatta National hospital's Blood Transfusion Unit (BTU) meet these standards. Objectives: The objectives of this study were to assess the processes employed in preparation of the concentrates and to determine and describe several quality parameters of platelet concentrates prepared by the Kenyatta National Hospital (KNH) Blood Transfusion Unit, and to determine whether these parameters met the minimum standards set by standards committee of NBTS. Methodology: This was a laboratory based cross-sectional study performed at KNH BTU between February and May 20 IO. The processes of platelet concentrate preparation (centrifugation, separation storage and agitation) were directly observed and scored on a Lickert Scale based on completion of the process. Platelet concentrate parameters (pH, volume and cell counts) were determined and recorded for comparison with NBTS standards. Data was analysed using means, median and standard deviations and presented in tables and figures. The student's t test was used to compare the degree of agreement of the characteristics of concentrates that met the minimum standards and those that did not meet the standards. Results: A total of 78 platelet concentrates were analysed. Centrifugation of whole blood was performed according to specification for all (100% n=78) concentrates. Separation was achieved by a separator but there was a prolonged delay of more than 1 hour before separation. Storage for all concentrates (100%, n=78) was in ambient temperature without temperature regulation. Agitation for all the concentrates ( 100%, n=78) was by circular motion in the horizontal plane. Only 51% (40) of all concentrates fulfilled the minimum specification for platelet count, none fulfilled specification for residual WBe:; count, whereas 91% (71) and 95% (74) of the concentrates fulfilled the standards for volume and pH respectively. Only 6 (7.6%) of the concentrates did not have red cell contamination. Conclusions and recommendations: The processes of separation,storage and agitation used in the preparation of platelets did not conform to the standards prescribed by NBTS.Only half of platelet concentrates prepared by the BTU fulfilled minimum specifications set by NETS for platelet counts.None met criteria for residual WBC count.The concentrates fulfilled criteria for volume and pH. There is therefore need to strengthen the quality assurance programme for platelet concentrates at KNH BTU that should include process control, development and adherence to standard operating procedures,and internal and external quality control.In addition it is recommended that all platelet concentrates prepared at KNH be subjected to platelet count before issue so that only those concentrates that meet quality standards are issued.