Sobani et al developed an algorithm for evaluating blood donors in Pakistan. This can help to decide how to triage blood products in order to avoid transfusion-associated malaria. The authors are from Aga Khan University and the Johns Hopkins University.
Subject selection: blood donor with some likelihood of having malaria
Parameters:
(1) residence in a town or city endemic for malaria
(2) documented malaria in past 3 years
(3) intermittent fever followed by sweating
(4) history of recurrent childhood fever
(5) chills
(6) rigors
(7) history of blood transfusion
(8) recent family history of malaria
(9) anyone known to have malaria in residential area (neighborhood)
(10) recent history of travel from a non-endemic to an endemic area
(11) documented malaria in the past 5 years
(12) other non-specific symptoms
|
Parameter |
Finding |
Points |
|
residence |
endemic for malaria |
2 |
|
|
non-endemic but travel to endemic area |
1 |
|
|
non-endemic without travel to endemic area |
0 |
|
documented malaria |
within past 3 years |
2 |
|
|
with past 4-5 years |
1 |
|
|
none or > 5 years ago |
0 |
|
intermittent fevers followed by sweating |
no |
0 |
|
|
yes |
1 |
|
history of recurrent childhood fever |
no |
0 |
|
|
yes |
1 |
|
chills |
no |
0 |
|
|
yes |
1 |
|
rigors |
no |
0 |
|
|
yes |
1 |
|
history of blood transusion |
no |
0 |
|
|
yes |
1 |
|
recent malaria in family member |
no |
0 |
|
|
yes |
1 |
|
anyone with malaria in residential area |
no |
0 |
|
|
yes |
1 |
|
other non-specific symptoms |
no |
0 |
|
|
yes |
1 |
where:
• The original wording is 2 points for malaria in past 3 years and 1 point for malaria in past 5 years.
• The original wording is 2 points for residence in a region endemic for malaria and 1 point for travel from non-endemic to endemic region.
total score =
= SUM(points for all 12 parameters)
Interpretation:
• minimum score: 0
• maximum score: 12 (as scored based on comments above), 14 if scored alternatively
• The higher the score the greater the risk for malaria in the donor.
• One modification is to make no risk as a score of 0 or 1. A person with a history of documented malaria in the past 3 years probably should have the blood tested.
|
Score |
Risk |
Additional Testing |
|
0 to 2 |
none |
none |
|
3 or 4 |
low |
antigen-based rapid test, reject if positive |
|
5 to 10 |
moderate |
microscopy with rapid diagnostic test if microscopy negative, reject if either positive |
|
>= 11 |
high |
reject product |
Alternative testing such as PCR could be performed if there is any risk of malaria in the donor.
There is a need to balance patient safety, cost of testing and blood supply. In a region endemic for malaria you cannot afford to reject all donors.
Specialty: Clinical Laboratory
ICD-10: ,
