Detection of hepatitis C viral sequences in blood donations by "nested" polymerase chain reaction and prediction of infectivity.

Of 1100 blood donations tested during a prospective study of post-transfusion non-A, non-B hepatitis (NANBH), 6 (0.55%) were repeatedly reactive in a commercial assay for antibodies to the C100 protein of hepatitis C virus. Only 1 of the 6 donations (17%) transmitted NANBH to a recipient.

Preliminary report: accurate assays for anti-HIV in urine.

Untreated urine specimens from 358 patients (344 attending genito-urinary medicine clinics, 14 haemophiliacs) and 353 blood donors were tested blind by a simple IgG-capture particle-adherence test (GACPAT) and a rapid IgG-capture enzyme-linked immunosorbent assay (GACELISA) for antibody to human immunodeficiency virus (anti-HIV). All 158 urine specimens from seropositive subjects were anti-HIV positive by GACPAT and 157 of them (99.4%) were positive by GACELISA.

Recombinant-based competitive anti-HIV assay: solution of some operating problems.

Using the Wellcozyme anti-HIV recombinant assay at 47 degrees, a strongly reactive result with an anti-HIV positive serum sample could not be reproduced when the corresponding plasma sample was used. Dilution in anti-HIV negative serum or kaolin treatment of the plasma specimen produced the clear reactivity seen with the serum sample, and a reduction in incubator temperature was also found to reduce this 'plasma effect'. Problems were also encountered initially when haemolysed serum or plasma with non-standard concentrations of anticoagulant were tested.

Use of a bacterial sampler for rapid transfer of microvolumes into microplates.

A method has been devised to transfer very small volumes of serum from microplates prepared during routine screening of blood into microplates containing diluent. Simultaneous transfer of 96 samples is achieved without the need for disposable tips, while still avoiding carry-over between different plates. Using this method a mean transfer volume of 0.

Screening plasma donors for high-titre antibody to cytomegalovirus using a latex agglutination test.

Cytomegalovirus (CMV) can cause severe morbidity in immunosuppressed patients. Regional transfusion centres in the UK are required to supply high-titre anti-CMV plasma to the Blood Products Laboratory (BPL), now called 'Bio-Products Laboratory', for the production of specific intravenous immunoglobulin at the Protein Fractionation Centre in Scotland. For this purpose, 703 plasmapheresis donors were screened by a modified latex agglutination test to assess their suitability as donors with high-titre anti-CMV.

Microbiological screening of blood donations: cost versus effectiveness.

The already considerable list of pre-transfusion microbial screening tests may well increase. Some American opinion favours attempting to achieve a 'zero-risk' blood supply by introducing extra tests. However, as well as being theoretically unattainable, 'zero-risk' causes practical problems as the efficacy of a screening test is often predicted, not proven.

Gelatin particle agglutination assay for HIV antibodies: a rapid, economical modification with increased sensitivity.

Modification of a commercial gelatin particle agglutination assay for anti-HIV reduces the test time to 30 min, increases the sensitivity sevenfold without any prozoning, and maintains specificity while cutting the cost of the test by 90%. The modification involves a tenfold dilution of the gelatin particles, which are added to a dilution of test serum in a 'V' well standard microplate. After incubation, plates are centrifuged briefly and allowed to stand at an inclination of 70 degrees until positive and negative reactions are clearly distinguishable within approximately 15 min.

Provision of a panel of anti-toxoplasma-negative blood donors.

Toxoplasma gondii has been reported to cause complications only in immunosuppressed patients receiving leucocyte transfusion, when severe acute toxoplasmosis has been reported with associated mortality. At the North London Blood Transfusion Centre (NLBTC) we have screened 392 plasmapheresis donors (using toxoreagent latex agglutination test manufactured by Eiken) to provide a panel of blood donors negative for antibody to toxoplasma for seronegative recipients. A toxoplasma-negative panel of donors would only be required for those rare instances when granulocyte concentrates are indicated for transfusion of seronegative recipients.

Rapid transfer of small volumes of serum into microplates.

A method has been devised to transfer small volumes of serum, as an adjunct to larger volume sampling, into microplates. The Costar Transplate 96 machine is used routinely in our laboratory for transferring serum samples into reaction wells for anti-HIV screening. Using this additional method a mean of 4 microliters of serum was transferred, within acceptable limits of error (coefficient of variation, c.

Cytomegalovirus screened blood for neonatal intensive care units.

Two infants were considered to have acquired cytomegalovirus (CMV) infection from blood transfusions screened for the presence of CMV antibody by a haemagglutination assay. Further samples from the same donors were tested by a latex agglutination test; six of 18 (33%) previously believed seronegative were found to be seropositive.

Serum alanine aminotransferase (ALT) and gamma-glutamyltransferase (gamma-GT) activities in north London blood donors.

Serum alanine aminotransferase (ALT) and gamma-glutamyltransferase (gamma-GT) activities were measured in over 2000 north London blood donors. The results were compared with those from the United States. The percentage of the total donor population with ALT activities above 40 IU/l in 1986 was greater than that found in our earlier studies in 1973 and 1982 (4.

Cytomegalovirus and blood transfusion.

The problem of transfusion-transmitted cytomegalovirus (CMV) infection differs from that for other transfusion-transmitted infections in that only patients who are immunocompromised require CMV-free blood or components. The virus is cell-associated and transmission appears to be due to reactivation of latent virus in white blood cells. As a herpes virus, CMV can be responsible for primary infections, reactivations or reinfections in humans.

HIV infection due to a platelet transfusion after allogeneic bone marrow transplantation.

A 30-yr-old man with chronic granulocytic leukaemia received a bone marrow transplant from his histocompatible sister in December 1982. His post-transplant course was complicated by Grade III graft-versus-host disease and multiple infectious episodes until his death from pneumonia on d + 190. He was later found to be seropositive for anti-HIV at the time of his death.