Proficiency in testing for hepatitis B surface antigen: experience with Ausria II

Area of Science:

• * Clinical Chemistry
• * Immunology
• * Public Health

Background:

• * Hepatitis B surface antigen (HBsAg) testing is crucial for blood safety.
• * Radioimmunoassay (RIA) kits were the standard for HBsAg detection in the late 1970s.
• * Ensuring the accuracy and reliability of diagnostic tests is paramount in blood services.

Purpose of the Study:

• * To evaluate the performance of HBsAg proficiency panels using RIA test kits.
• * To identify potential sources of error and variability in HBsAg testing.
• * To recommend improvements for HBsAg test validation and accuracy.

Main Methods:

• * Eight HBsAg proficiency panels were tested.
• * Testing was conducted by routine laboratories in American Red Cross Blood Services Regions.
• * Radioimmunoassay (RIA) test kits were utilized during 1978-1979.

Main Results:

• * Analysis revealed significant lot-to-lot variability in the RIA test kit reagents.
• * This variability was associated with a measurable loss of test sensitivity.
• * An increased error rate in HBsAg detection was observed due to reagent inconsistencies.

Conclusions:

• * Lot-to-lot reagent variability poses a risk to HBsAg testing accuracy.
• * The positive to negative (P/N) ratio is a critical parameter for test validation.
• * Recommending an increased P/N ratio to at least 25 can enhance test sensitivity and reduce errors.