DDr.Susheela Innah Professor &HoD Dept of Transfusion Medicine Jubilee Mission Medical College, Thrissur

 In 1910 Duke first noted that platelets from whole blood reduce the bleeding time  In 1950s platelets were collected and transfused, but only for diagnostic purposes.  In 1960s plastic blood bags became available which enabled platelets to be separated from whole blood collections by centrifugation.

 In the 1970s Drs. Scott Murphy and Frank Gardner discovered that platelet function was best preserved if the platelets were stored at room temperature with agitation. This resulted in the introduction of prophylactic platelet transfusions for patients with leukaemia.  In the 1980s new methods for platelet transfusion were introduced using cytapheresis technique  In the 1990s cytapheresis methods was refined by collecting leucocyte reduced platelet products.

Platelets are obtained by three different methods:  Platelet concentrates from whole blood by hard spin (Random donor platelets) - RDP  Buffy coat removed platelet concentrate – BCR-P  Apheresis Platelets (Single Donor Platelets) - SDP

RBCsPRP Plasma Platelet concentrate

 The hard-spinning of the platelets on to the bottom of the bag in the PRP method, requiring re-suspension of the plts, may induce a collection injury that could potentially compromise the long-term storage of PRP platelets compared with BC platelets. However, there is currently no direct evidence to substantiate this hypothesis Transfusion 1989;29: Blood 2003;102:93a. Blood 2006;108:282a-283a.

Buffy coat removed cells prepared by centrifugation and separation by automated Component separator

PPP BC BCR-RBC WB Preparation of leuco-reduced components using top and bottom bags with optipress

Optipress with PPP and RBC Optipress with PPP and RBC

PPP BC BCR-RBC PPP BCR-RBC BC Buffy coat Buffy coat

Buffy Coat is hung

BC-PC BCR BC-PC Leuco-reduced platelets Leuco-reduced platelets BC

BCP BC Sterile connecting device for preparing pooled platelets

 Single-donor apheresis platelet concentrates may be collected by a variety of apheresis systems, using different protocols. Platelet yields may vary, and each procedure or protocol must be fully validated, documented and specifications set.

Random donor platelets Buffy coat platelets Cytapheresis platelets PreparationPrepared from centrifugation of whole blood derived platelet rich plasma Prepared from centrifugation of whole blood derived buffy coats Prepared by apheresis from a single donor Donor numberMultiple One Volume45-50 ml ml Platelets5.5 x x x Properties of platelet concentrates

Random donor platelets Buffy coat platelets Cytapheresis platelets Leucocytes7-9 x x 10 7 < 1 x 10 6 Red Cells< 1 mlrare< 1 ml pH Bacterial contamination 2.5%0.12%

Random donor platelets Buffy coat platelets Cytapheresis platelets IL-1 (Day 1) 06 pg/ml 0 IL-6 (Day 1) 140 pg/mL73 pg/mL<15 pg/mL IL-8 (Day 1) 100 pg/mL 489 pg/mL 170 pg/mL TGFa(Day 1)11,050 pg/mL2,900 pg/mL2,670 pg/mL AUSTRALASIAN SOCIETY OF BLOOD TRANSFUSION Topics in Transfusion Medicine February 2001 Vol 8 No 1

RDP BCR -PSDP Cost Rs For 6 units Rs 3000 – 4000 For 6 units Rs 9000 to for 1 unit Side-effects of Transfusion Same Post-transfusion increments, haemostatic effectiveness Same Donor Exposure Multiple Single

RDP BCR -PSDP AlloimmunizationDevelops only in minority of patients on chemotherapy Lesser than RDP Less chances Inventory Management Sufficient stock can be managed on a daily basis Difficult to obtain during emergency and holidays

 Thus administering random donor platelets followed by single donor platelets if alloimmunization develops, is justified by both economic and scientific reasoning.