1. Platelet Refractoriness
Laura Cooling MD, MS
Associate Medical Director
Transfusion Medicine

2. Platelet Kinetics circulating life span 8-10 days
Circulation
60%
Spleen
30-40%
10-12% loss/day
20% endothelial integrity
80% senescence

3. Definitions of Refractoriness
2-3 consecutive platelet transfusions by CCI or PPR
REFRACTORINESS
ALLOIMMUNIZATION

4. Platelet Refractoriness
Poor response to platelet by immune or nonimmune factors
Immune (25-50%)
Alloimmunization
Autoantibodies
Passive Immunity
Drug-related
Nonimmune (50-75%)
Fever
Infection
Splenomegaly
Drugs/Antibiotics
Consumption
Bleeding
Platelet Dose

5. Effect of Platelet Count, Splenomegaly
and “Refractoriness” on Platelet Survival
Normal
Plt>200K
75%
65%
50%
Asplenia
Refractory
Normal
Plt<50K
Splenomegaly
Plt<50K
1 hr
20-24 hr
2 days
8-10 days

6. Platelet Response and Kinetics in Normal and Refractory Patients
PPR = 60-66%
Normal
PPR>30%
20-24 hrs
% Platelet Recovery (PPR)
Immune
Hypersplenism
Nonimmune
24 hrs

7. Evaluating Platelet Transfusion Response
Corrected Count Increment (CCI):
In vivo Measurement Platelet Survival
Number of Platelets Transfused
Size of Patient
Requires a 1-4 hour post-platelet count
Positive Predictor platelet survival at 20 hrs

8. Corrected Count Increment
Whole Blood Derived Platelet Concentrates
CCI= (post-platelet count - pre-platelet count)(BSA)
(3.5 [approximate # platelets transfused x 1011])
CCI > 7.5 Good Response
* Platelet count at 1 hour post transfusion,
BSA=body surface area in M 2
Example: Patient (1.7 M 2) transfused with 5 units pooled platelets for platelet count=2. At 1 hr, plts=30K. CCI=(30-2)(1.7)/3.5=13.6

9. Specialty Products Documented Refractory Patients
Pathology consultation and approval
Crossmatched Platelets (First Choice)
Single donor apheresis platelets “crossmatched” solid-phase technique with patient’s serum
HLA Platelets
require HLA antibody screen + HLA type
Antigen negative: lack specific HLA antigens
HLA-matched: A or B matches only, require 8-10 days from Los Angeles Red Cross

10. Influence of Patient Factors and Storage Time on Platelet Transfusion Response* *Slichter 1997, adapted from Norol 1994 NS
p<0.05
p<0.05
p<0.05
89%
65%
51%
21%
13%

11. Comparison of Mean PPR with Random, HLA (Antigen Negative and Matched), or Crossmatched Platelets Petz et al. Transfusion 2000;40:
Mean PPR

12. Percent of HLA-Matched (A+BU) vs HLA-Antigen Negative Compatible Platelet Donors per Patient Petz et al. Transfusion 2000;40:
33.8
28.8
18.6
% HLA Typed Donors (n=7247)
9.5
2.1
0.7
0.6
0.6
0.1
0.3

13. Corrected Count Increment
CCI: Apheresis Platelet Concentrates
=(Post-platelet count - Pre-platelet count)(BSA)*
# platelets transfused (x1011)
CCI >7500 (1 hr) or >5000 (20 hr)
* Body surface area (M2)
Ex. A woman transfused with SDP (4 x 1011).
Platelet count pre=8, post=42. BSA=1.5 M2
CCI=(42-8)(1.5)/4=12.7

14. Percentage Platelet Recovery (PPR)
Percent Predicted Count (PPC)
=No. platelets transfused x 0.67 x .001
blood volume (mL)
Percent Platelet Recovery (PPR)
= (post-platelet - pre-platelet count)x 100%
percent predicted count
Normal = PPR 60% (1 hr) or > 30% (20 hr)
Refractoriness = PPR < 30% (1 hr) or < 20% (20 hr)