The Blood Transfusion Service introduced screening for Hepatitis C ant
ibody (HCV) in September 1991. This is done by second generation enzym
e linked immunosorbent assay (ELISA) tests. We present a case of post-
transfusion hepatitis C hepatitis in a patient with myeloma. Infection
was acquired before screening was introduced. Both the patient and th
e infected blood donor were diagnosed using ELISA assays and the polym
erase chain reaction (PCR). In this way we prevented the blood donor f
rom spreading the virus via subsequent blood donations. There were som
e interesting discrepancies in the HCV assays. Blood samples, when tes
ted by different methods, gave both positive and negative results. The
results also varied according to when the blood samples to be tested
were taken. The case illustrates the importance of confirming positive
results and that no single laboratory test is entirely satisfactory i
n diagnosing HCV infection.