Surrogate testing for non-A, non-B hepatitis

Prevalence and consistency of ALT elevation in plasmapheresis donors: implications for the assessment of blood product infectivity

Alanine aminotransferase (ALT) levels were determined in 8,420 plasmapheresis donations obtained from 431 donors over a period of 18 months. Using sex-differentiated normal ranges 2.5% of donations but 23% of donors exhibited elevated ALT levels on at least 1 occasion. Amongst the donors with elevated ALT this was only seen on 1 occasion in one third, while a quarter had elevations in consecutive donations. No donors with consecutive elevations above 100 IU/l were detected. The results are discussed in terms of the guidelines currently recommended for assessing post-transfusion hepatitis infectivity of blood products, such as factor VIII. It is concluded that the current allowance for infection acquired from sources other than blood products under consideration may be over-generous, leading to a potential underestimate of the true rate of infection.

Low incidence of non-A, non-B post-transfusion hepatitis in London confirmed by hepatitis C virus serology

To see whether the introduction of screening tests for post-transfusion non-A, non-B hepatitis (NANBH) in the UK would be worth while, the incidence of such hepatitis was assessed among patients receiving blood during operations at five hospitals served by the North London Blood Transfusion Centre. 387 patients, who each received blood or blood components from an average of 3 donors were followed up prospectively and blood samples were taken every 2 weeks for 3 months and then each month for a further 3 months. 229 patients also provided a sample at 12 months. All available patient and donor samples were tested for alanine aminotransferase concentrations and for antibody to hepatitis C virus (anti-HCV) by ELISA. Repeatedly anti-HCV positive samples were submitted to supplementary HCV assays. 1 of the 387 patients showed biochemical evidence of acute post-transfusion NANBH after exclusion of non-viral causes. Anti-HCV developed in this patient and the seroconversion was confirmed by recombinant immunoblot assay and polymerase chain reaction. Serum from 1 of the 8 donors whose blood he received was positive for anti-HCV by all three methods. In another patient HCV seroconversion was shown by ELISA but alanine aminotransferase concentrations remained normal throughout follow-up. His samples and those of his 2 donors were negative for HCV by the polymerase chain reaction. A third patient showed rises in alanine aminotransferase compatible with post-transfusion NANBH, but serology and polymerase chain reaction assays for HCV were negative for her samples and those of her donors. Anti-HCV reactivity likely to be false positive (negative by both confirmatory tests and no adverse effects in recipients) was seen in 6 of 1283 donors. This study, despite its being carried out in the part of the UK with the highest frequency of infectious markers in blood donations, has shown a very low incidence of post-transfusion NANBH.

Infectious complications of blood transfusion

Numerous infectious diseases are transmissible by blood, with AIDS and hepatitis being the predominant concerns today. Less in the limelight, but nonetheless blood transmissible, are cytomegalovirus infection, malaria, babesiosis, and hepatitis B. A major controversy with respect to non-A non-B hepatitis relates to the use of 'surrogate' testing of donors for ALT and hepatitis B core antibody. Transfusion-associated AIDS has been markedly reduced as a risk, due to blood donor antibody screening implemented in March 1985. However, other retroviruses such as HTLV-1, HTLV-II and HIV-II pose additional concerns regarding the safety of the blood supply, and decisions will be forthcoming regarding testing of donated blood for antibody to these viruses.

Microtitre plate method for alanine transferase (ALT) assays

A kinetic assay for alanine transferase (ALT) using microtitre plates and commercially available reagents was developed to retain the advantages conferred by multichannel and semiautomated equipment. The time taken to assay 92 samples was less than 10 minutes, and costs of apparatus and reagents compared favourably with most current methods. Although reactions became non-linear above 120 IU/l-1, higher concentrations were "flagged" and accuracy was satisfactory below this point.

Urinary neopterin levels in acute viral hepatitis

Elevated neopterin levels in blood or urine have been shown to be a marker for the activation of cell-mediated immunity in vitro and in vivo. To evaluate whether neopterin levels are elevated in patients with acute viral hepatitis, we measured urinary levels in 13 patients with hepatitis A, 26 with hepatitis B, 12 with non-A, non-B hepatitis, 8 with jaundice and/or cholestasis due to biliary and pancreatic disorders and 3 with alcoholic hepatitis and in 62 apparently healthy HBsAg carriers. Neopterin levels in patients with virus-induced hepatitis were significantly higher than those in patients with other diagnoses. Urinary neopterin levels were above normal in 49 of 51 patients with viral hepatitis and elevations during the course of hepatitis showed a pattern similar to that of the usual liver biochemical tests, suggesting that neopterin levels were related to the clinical activity of the viral disease. In patients with nonviral biliary and hepatic disorders, neopterin levels were usually normal and did not correlate with other liver biochemical tests. These findings suggest that cell-mediated immune mechanisms are activated during viral hepatitis and that neopterin measurement may be of value as an additional surrogate marker for non-A, non-B hepatitis.

Surrogate testing for non-A, non-B hepatitis in Queensland, Australia: an ALT microtitre tray method for screening blood donors

The estimation of plasma alanine aminotransferase (ALT) has been proposed as a surrogate test to identify potential non-A, non-B hepatitis carriers in blood donor populations. This report describes an ALT screening procedure which uses wells of microtitration trays as reactant vessels. The method utilizes a rate reading photometer, is economical and conveniently fits into the routine workflow. Within-batch and between-batch precision was 4.1% and 6.3% at enzyme concentrations of 49 IU/I. Results of testing 29,675 healthy blood donors gave values which ranged between 1.0 IU/I and 214 IU/I. A study of 762 donations showed a significant difference in mean ALT values between males and females (p less than 0.01). When a cut-off value of 46 IU/I was used, 2.5 percent of donations were considered unsuitable for transfusion. The medico-legal implications that may arise from the introduction of this screening test into the routine work flow are discussed.

Incidence and significance of hepatitis B core antibody in a healthy blood donor population

To determine the current incidence of hepatitis B core antibody (anti-HBc) in a healthy blood donor population, 1,893 donors were screened for anti-HBc. Forty-one (2.16%) were found to be initially positive and 35 (1.85%) repeatably positive. Sera from the repeatably positive donors were further screened for hepatitis B surface antibody (anti-HBs), and hepatitis B virus DNA (HBV DNA) by dot hybridisation. The repeatably positive donors were subsequently recalled for further investigation, and their peripheral blood lymphocytes were also screened for HBV DNA by dot hybridisation. Eighteen (51.4%) of the anti-HBc-positive donors were also anti-HBs-positive. HBV DNA was not detected in the serum or the lymphocytes of any of the anti-HBc-positive donors.

Hepatitis B markers in Lancashire police officers

A total of 284 Lancashire police officers each with a minimum of 5 years experience was tested for evidence of hepatitis B infection. None was hepatitis B surface antigen positive (HBsAg). Three were positive for both antibody to hepatitis B core antigen (anti-HBc) and HBsAg (anti-HBs). Five were positive for anti-HBc alone. Thus the overall prevalence was 2.8% which is within the range reported for blood donors in the UK. There was no association with working in the drug squad or custody office but there was a higher prevalence in those who had worked in the scene-of-crime's squad. However, the numbers were small, and of this group of 28 officers, 2 of the 3 with detectable hepatitis B markers were positive for anti-HBc alone. Therefore for police officers in mixed rural/urban areas of the UK, routine administration of hepatitis B vaccine is not justified although special consideration should be given to those working in selected groups. Further studies are required to ascertain whether there may be an increased risk for police officers working in conurbations.