Determination in vivo viability of a transfused platelet product by corrected count increment and percentage platelet response.

INTRODUCTION: For many years, platelet concentrates have been used for the prevention as well as treatment of bleeding disorders, especially in those patients with haematological problems involving platelet disorders as well as refractoriness, In addition, platelet concentrates (PCs) have been widely used to support patients undergoing bone marrow transplantation or who are receiving myelotoxic treatments. The aim of this study was to determine the quality of platelet concentrates by assessing platelet counts, volume, pH changes, swirling, residue of the red blood cells and white blood cell counts. Assess the in vivo viability of a transfused platelet product using the corrected count increment (CCI) and the percentage platelets response (PPR). This descriptive analysis study was done in Kenyatta National Hospital Blood Transfusion Unit between July 2016 and December 2016.

METHODS: The in vitro Platelets concentrates quality was accurately determined and assessed using certain parameters. Platelet concentrates in ethylene diamine tetra acetic acid (EDTA) was used for analysis using Cell-Dyn 3700 analyser. The volume of PCs used was an average of 2mls of PCs, the pH was measured using digitalised Hanna edge pH kit. Agitation was done using Helmer agitator and centrifugation was done using Roto silenta 630 RS centrifuge. The in vivo viability of a transfused product was determined using corrected count increment (CCI) and percentage recovery (PR) between 1 and 20-hour after transfusion. Pre and post-transfused whole blood in EDTA collected from the recipients was analysed to access the functional platelets in the circulation. Data analysis was done using SPSS.

RESULTS: A total of 384 platelet concentrates were analysed and used in transfusion. The majority 96, (40%) were O Rhesus D+ and the least being AB Rhesus D-at (1%).Centrifugation, separation and agitation was done according to standard procedure (n=384). Only (246 (65%) of the concentrates were found fit for use out of a total of (n=384) leaving 138 (35%) which did not meet the KNH/KNBTS criteria. The minimum specifications for platelet count are 5.5 x (109 ). The duration of 3 days of storage on average, the WBC count (109 ) was Mean ± SD 4.50 ± 3.50. Using the Hanna edge pH kit the pH Mean was ±SD 7.18 ± 8.82 and the used Volume (Mls) was at 55 ± 15. The concentrate was issued within 3 days of processing. After transfusion, the percentage platelet response (PPR) was 72% in male recipients at 1-hour and 30% at 20-hours while 69% in female recipients at 1-hour and 25% at 20-hours. The invivo viability of platelet product had a corrected count increment (CCI) of 75% ≥ 7500 at 1-hour and CCI of18% ≥ 30% at 20-hours in male recipients. In the same study, the female recipients had a CCI of 80% ≥ 7500 at 1-hour and a CCI of 25% ≥ 30% at 20-hours.

CONCLUSION: The findings on platelets concentrates quality 65% met platelets transfusion criteria while 35% did not. On preparation of platelets concentrates there was high counts of white blood cells 4.5±3.5×109 than recommended counts by Kenya National Blood Transfusion Services < 0.83×109 . Both percentage platelet response (PPR) and corrected count increment (CCI) were very low at 20 hours compared to British committee for standards haematology criteria for successful increment of platelet products (PPR ≥ 30% and CCI ≥ 7500). Apheresis platelets transfusion can be introduced at KNH and use of leukoreduction performed on the platelet concentrates which are prepared within the Hospital. With such rate of refractoriness, additional tests to confirm the real cause of unviability of platelets in the patients need to be performed. Recipients should be done evaluation of the pattern of refractoriness followed by HLA compatibility testing. In addition, if there is a high, compatible cross-matched, selected apheresis platelet concentrate pint should be transfused. This unviability was due to recipients with either immune-mediated refractoriness or non-immune mediated refractoriness.