Prediction of the Platelet Count Increment (CI) After Platelet Transfusion Using the Equation of Bishop et al

 

NOTE: The CI is the same as the CCI (above).

 

Platelet transfusions were done using random concentrates from non-HLA-matched volunteer donors, with 6 units pooled. The average number of platelets per concentrate was 71 billion. Analysis was based on 1 transfusion per patient.

 

Indications for platelet transfusion:

(1) if platelet count < 20,000 per µL, either prophylactically or if the patient was bleeding;

(2) if the patient was bleeding with a platelet count >= 20,000 per µL.

Parameters:

(1) splenectomy

(2) bone marrow transplantation

(3) DIC

(4) amphotericin B

(5) palpable spleen

(6) HLA antibody grade

(7) platelet specific antibody score, from 0 to 4)

(8) number of antibacterial antibiotics

(9) clinical bleeding

(10) body temperature

Parameter	Finding	Points
history of splenectomy	no	0
	yes	1
history of bone marrow transplantation (BMT)	no	0
	yes	1
DIC	absent	0
	present	1
amphotericin B	not given	0
	being given	1
palpable spleen	no	0
	yes	1
HLA antibody grade	grade 0 to 4	(antibody grade)
platelet specific antibody score	score 0 or 1	0
	score 2, 3 or 4	1
number of antibacterial antibiotics		(number of antibiotics)
clinical bleeding	absent	0
	present	1
body temperature	temperature in °C	(temperature) – 37°

 

where:

• A splenectomy means that the value for palpable spleen is 0.

• The HLA antibody grade was based on testing the patient sera against 100 lymphocytes of known antigen type: 0% grade 0; 1-9% grade 1; 10-49% grade 2; 50-74% grade 3; 75-100% grade 4.

• Platelet specific antibodies: The patient sera was tested against 4 platelet samples from 4 random donors using a platelet immunofluorescence test (PIFT) and against 4 lymphocyte samples from the same donors using lymphocyte toxicity (LCT). Platelet specific antibodies were considered present if the PIFT was positive and the LCT negative. The platelet specific antibody score was the number of donors showing platelet specific antibodies.

• It would appear that a low body temperature would impart a positive value to the estimated CCI. It may be that a value < 37°C should be given a value of 0, or that the absolute value of the difference should be used. I used the former approach in the implementation.

 

estimated CCI in 10^9/L or 10^3/µL =

= 17.8 + (7.7 * (points for splenectomy)) – (6.2 * (points for BMT)) – (4.1 * (points for DIC)) – (4.1 * (points for amphotericin)) – (3.5 * (points for palpable spleen)) – (3.1 * (points for HLA antibody grade)) – (0.9 * (points for platelet specific antibody score)) – (0.7 * (points for antibacterial antibiotics)) + (0.4 * (points for clinical bleeding)) – (0.3 * (points for body temperature))