Comparison of in vivo outcome following transfusion of dynamic light scattering-screened versus unscreened platelets

1. 24 hour corrected count increment (CCI24h); the transfusion outcome of each platelet transfusion will be determined by documenting the platelet survival in patient circulation at 24 hours. This is the primary outcome. The corrected count increment (CCI) is an automated calculation using the established formula which cannot be influenced by the software user. CCI will be calculated by the laboratory research assistant from the pre-and post-transfusion platelet counts, normalized to the body surface area.
Corrected count increments (CCIs) are calculated using the following formula:
CCI = (post count – pre count) x BSA / platelet dose x 1011
Where body surface area (BSA) is calculated based on patient height and weight using :
BSA [m²] = 0.007184 x Height [cm]0.725 x Weight [kg]0.425
2. Time to next platelet transfusion (hours), or inter-transfusion interval (ITI). Therapeutic or prophylactic platelet transfusions will be requested by the patient’s physician in accordance with international guidelines. Prophylactic PLT transfusions will be given to afebrile and clinically stable patients with peripheral blood PLT counts below 10 x 109/L and to febrile patients when PLT counts are below 20 x 109/L. In patients with increased risk of bleeding (e.g., before invasive procedures or recent hemorrhage) or ongoing bleeding, PLT transfusions will be administered when peripheral blood PLT counts are below 20 - 50 x 109/L and at physician discretion.
3. World Health Organization (WHO) bleeding score; administered by blinded research nurse daily and at 24 hours post platelet transfusion. The bleeding score will be assigned daily based on the severity of bleeding criteria. The following categories are evaluated:
3.1. No bleeding
3.2. Grade I - very mild bleeding
3.3. Grade II - mild, epistaxis, mucocutaneous, conjunctival bleeding
3.4. Grade III - moderate, greater than II, but not requiring RBC support
3.5. Grade IV - severe bleeding

The ThromboLUX score, produced by the instrument without user intervention, will be correlated to the three outcome measures: 24h CCI, ITI and WHO bleeding score.

1. Additional clinical information, known to impact platelet recovery and survival will be collected for each enrolled patient, including:
1.1. General Clinical Information:
1.1.1. Baseline Data for Enrolled Patients
1.1.2. Diagnosis
1.1.3. Planned Treatment (current admission)
1.1.4. Weight (calculated BSA)
1.1.5. Splenomegaly (Y/N)
1.1.6. HLA antibody screen status (if repeat admission)
1.2. Daily Clinical Data Collection during period of hypoproliferative thrombocytopenia (from first platelet count <50 x giga/L, or 1st platelet transfusion order, to Bone Marrow recovery (spontaneous platelet count >75 x giga/L)
1.2.1. Bleeding Score by WHO (Administered by blinded study RN)
1.2.2. Temperature (route)
1.2.3. Infection (Y/N) / culture results
1.2.4. Antibiotic therapy
1.2.5. Antifungal treatment
1.2.6. Granulocyte Cell Stimulating Factor (GCSF)
1.2.7. Platelet count
1.2.8. Hemoglobin
1.2.9. Known Graft versus Host (organ(s) and grade)
1.2.10. Coagulopathy (International Normalized Ratio [INR], Partial Thromboplastin Time [PTT], Thrombin Time [TT], Fibrinogen, D dimer if available)
1.2.11. Positive anti-HLA antibody screen or CBS antibody testing (detail/date of sample)
1.2.12. Red Blood Cell (RBC) Transfusion (# units, and indication)
1.2.13. Platelet Transfusion (indication)
1.2.14. Procedure planned/ special notes
1.3. With Each Platelet Transfusion
1.3.1. Time initiated
1.3.2. ABO compatibility
1.3.3. Matched
1.3.4. Major Incompatible
1.3.5. Minor Incompatible
1.3.6. Bidirectional incompatibility
1.3.7. Transfusion Reaction (Type)
1.3.8. 1 hour post platelet count (45-120 min)
1.3.9. 24 hour post platelet count (18-24h)
2. Data Collected for each Platelet concentrate transfused to a study patient (screened or control arm) includes:
2.1. Data provided on product label
2.1.1. Platelet count of product
2.1.2. Type of platelet product (Apheresis or buffy coat pool)
2.2. Data obtained from analysis of sterile sample from platelet bag
2.2.1. Thrombolux score
2.2.2. pH
2.2.3. Morphology
All platelet concentrates will be gamma irradiated prior to issue with VGH Cesium source blood product irradiator. (Canadian Nuclear Safety Commission License No: 03323-2-12-0)
3. Additional testing on existing Patient blood sample post transfusion (for selected transfusion events):
For platelet transfusions where one hour post transfusion platelet count exceeds the sum of pre-transfusion count plus the transfused platelet dose plus two standard deviations, the post transfusion patient EDTA sample will be procured from the hematology laboratory and transferred to the centre for blood research laboratory for further testing. Testing will include CD41 and CD61 by flow cytometry.