Eroneous
results in serological testing may prove fatal in a blood transfusion
laboratory.
All
laboratory samples must be preserved for at least 7 days after the test. Any
transfusion reactions reported to the blood transfusion service must be
properly worked-up with detailed repeat laboratory testing on donated unit and
recipient’s samples (pre-and post-transfusion). A complete record of the type
of transfusion reaction and results of the investigation must be kept.
Adequate
controls must be set up with each technique to avoid false reactions.
Screening for transfusion transmitted
diseases
Efforts are made in all tranfusion
services to reduce the risk for transfusion transmitted diseases. Infections
for which screening should be done depends on endemic infections in that area
e.g., parasite, bacteria and viruses; and funds availabfe.
It is mandatory in India, to screen all donated blood
unitsfar Hepatitis B viral
infection (HBsAg), HIV infection (anti-HIV-1 and anti-HIV-2), syphilis
(anti-treponemal antibodies by VDRLJTPHA test) and malaria (peripheral blood
smear examination), and HCV.
To achieve the goal of transfusion safety
and prevent transfusion -
transmitted
infections it is imperative to use highly sensitive and specific test assay
systems to detect weak reactions.
The test assay system or test kits should
be revalidated. Procedures should be strictly adhered to and appropriate test
and internal control (positive and negative) must be put with each batch of
test. A test run validity and proper calculations are also important to avoid
any false-negative or positive results.
The donated units with a positive marker
of infection must be isolated soon after completion of the tes and discarded
after proper disinfection or incinerated if facility is available.
A continuous supply of validated test
kits is essential for successful screening of all donated units. Adequate
storage of kits at recommended temperature must be maintained for proper
functioning of the test kits and reagents.
