Blood screening began in Bangladesh in 2000 at all hospital based blood transfusion centres. It is the process that starts with the recruitment of safe blood donors and is followed by the mandatory screening for five transfusion transmissible infections (TTIs) which includes HIV, Hepatitis B, Hepatitis C, syphilis and malaria. Testing for TTIs started under the purview of the Safe Blood Transfusion Act 2002, which states that prior to transfusion, all blood and its products must undergo testing.
The objective of screening is to detect markers of infection, and prevent the release of infected blood and blood components for clinical use. The assay selected for screening should be highly sensitive and specific. The aim is to detect all possibly infected donations while minimizing wastage due to false positive results. Reactive donations that are confirmed positive, or in which results are indeterminate, should be discarded using methods in accordance with standard safety precautions.
Steps in blood screening
• Blood donor selection
• Self‐exclusion, deferral Laboratory testing: Detection of infection markers; either antibody or antigen Blood safety in the hospital setting
• Low risk blood donor recruitment
• Blood screening
• Rational use of blood
It is recommended to collect blood from non‐remunerated volunteer donors. The aim of using selection guidelines for blood donors has two purposes: firstly, to protect donors from potential harm which may occur as a direct result of the donation process; secondly, to protect recipients of blood transfusion from adverse effects, such as transmission of infectious diseases or other medical conditions and unwanted effects caused by medication taken by the donor.
In Bangladesh, donors are selected according the following important eligibility criteria:
• General appearance: the prospective donor shall appear to be in good physical and mental health.
• Age: donors shall be between 18 and 60 years of age.
• Haemoglobin: Hb shall be not less than 12.5 g/dL for males and 11.5 g/dL for females.
• Weight: minimum 45 kg.
• Blood pressure: systolic and diastolic pressures shall be normal (systolic: 100‐140 mm Hg and diastolic: 60‐90 mm Hg is recommended), without the aid of anti‐hypertensive medication.
• Temperature: oral temperature shall not exceed 37.5°C/99.5°F.
• Pulse: pulse shall be between 60 and 100 beats per minute and regular.
• Donation interval: the interval between blood donations shall be 3 to 4 months.
The donor should not be fasting before donation. If the last meal was taken more than four hours previously, the donor should be given something to eat and drink before donation. Blood flowing into the bag is mixed with anticoagulant in a ratio of 1:7 (anticoagulant: blood). Total collection volume is from 405‐495 mL and usually, a volume of 450 mL blood is donated, this being approximately 12% of total blood volume or 10.5 mL/kg body weight.