One of the biggest concerns people have is: “Can infected blood slip through and harm a patient?” To prevent this, every donation is tested using standardized methods before it is ever used.

Why infection screening is essential

Some people can carry infections without any symptoms. If their blood were transfused without testing, these infections could be passed on to patients, who may already be weak or seriously ill.

Major infections that can be spread by blood include:

·       HIV (Human Immunodeficiency Virus).

·       Hepatitis B.

·       Hepatitis C.

·       Syphilis.

·       In some regions, malaria and other specific infections.

Because of this, every unit is screened, even from regular, trusted donors.

What infections are usually tested

Although exact panels differ by country, most blood banks routinely test for:

·       HIV 1 & 2 – using sensitive tests that look for antibodies and often viral proteins.

·       Hepatitis B – usually HBsAg (surface antigen) and sometimes other markers.

·       Hepatitis C – anti‑HCV antibodies and, in some systems, direct viral tests.

·       Syphilis – with specific serological tests.

·       Malaria – in many malaria‑endemic regions, using rapid tests or microscopy.

Some advanced centres also use NAT (Nucleic Acid Testing), which can detect viral genetic material earlier than antibody tests.

How the testing process works

1.      During donation, in addition to the main bag, small sample tubes of your blood are collected.

2.     These tubes are labelled with your unique donation number, linked to your donor record.

3.     In the laboratory, trained technicians run the required tests on these samples.

4.     Test results are recorded in secure systems.

If all tests are negative (non‑reactive), the blood is considered safe from those infections (within the limits of current technology and the “window period”). If any test is reactive or positive:

·       The associated blood unit is discarded and never used for patients.

·       Additional confirmatory testing may be done on the sample.

·       The donor is usually contacted privately, counselled, and advised about medical follow‑up.

What is the “window period”?

The window period is the time just after a new infection when the virus is in the body but tests may not yet detect it. To reduce this risk:

·       Blood centres use highly sensitive tests.

·       Donor screening questions aim to identify people who might be in the early phase of infection and ask them not to donate.

This combined approach (careful questioning plus advanced testing) makes transfusion‑transmitted infections very uncommon in systems that follow recognized standards.