Malaria - Blood Banking
Question: In an endemic country, will I save blood donations by using the Cellabs kit compared with only using a questionnaire?
- Using the Cellabs kit is not recommended in blood banks from meso-endemic or hyper-endemic countries, where Malaria seropositives in the general population exceed 10%-15%.
- In hypo-endemic and non-endemic countries, you will save donations which you might otherwise have rejected based on the donor questionnaire. See Chiodini et al, 1997.
- The donor questionnaire may reject too many potential donors, simply based on the fact they live in Malaria endemic zones and are therefore at risk of having been infected by Malaria.
- By using the Cellabs Pan Malaria Antibody CELISA kit on donors potentially at risk, you will be able to identify only those donors which have indeed been exposed to malaria, but retain all donations (typically the vast majority) which show no sign of exposure.
Question: Is this kit designed for endemic countries?
- Yes, it is designed for use in hypo-endemic countries, where Malaria seropositives in the general population is below 10-15%. By screening blood donors against Malaria with the Cellabs kit you achieve 2 goals:
- You minimise the risk of Malaria transfusion transmission by rejecting any donation from a donor previously exposed to Malaria (which would give an elevated result by Pan Malaria Antibody CELISA).
- You maximise the number of healthy donations you can accept, avoiding to reject donors solely on questionnaire (see above question).
Question: How specific is the Cellabs KMC3 kit?
- Cellabs Pan Malaria Antibody CELISA is extremely specific for IgG antibodies to P. falciparum, P. vivax, P. malariae and P. ovale. The antigen detection used in the kit is a trade secret and is based on a complex cocktail of recombinant antigens.
- The specificity of the Cellabs kit is in part due to the use of a monoclonal antibody, and the initial 1:100 sample dilution which avoids non-specific binding & spurious results.
- The importance of proper dilution of serum samples in serology assays is demonstrated in the 1995 article by Abramo et al. which clearly states "Thus we recommend the use of sera diluted > 1:80 to exclude cross-reactive antibodies to this parasite in seroepidemiologic studies of Malaria."
Question: Can I detect acute Malaria cases with the Cellabs KMC3 kit?
- The vast majority of patients suffering from an acute case of malaria are not going to give blood without attracting attention: they will have clear clinical symptoms. They would present with clinical symptoms and would be detected during the pre-donation interview and questionnaire. However, in endemic countries, some rare individuals may have partial immunity, and could display very few symptoms or none at all. It is however a rare occurrence.
- The Pan Malaria Antibody CELISA kit is not intended to detect acute cases of infection; it is intended to detect exposure to the malaria parasite.
- However, experience shows that you will detect most (~ 70-75%) acute cases of P. falciparum and many (~ 50%) of the other acute cases of P. vivax.
Question: What should I do if I find an antibody positive sample?
- Most positive results come from patients with “old exposure”, who are not infectious at the time of the assay. You might still be able to use some components from the donation (like the plasma)
- You should firstly repeat the test to reconfirm its validity. Then you should consult the guidelines from your blood banking association like the ISBT or the AABB.
Question: Will using the Cellabs kit lead to excessive donor rejection?
- No. Typically the use of the Cellabs Pan Malaria Antibody CELISA kit results in less donor rejections when compared to the donor questionnaire alone (See Chiodini et al., 1997).