Authors' objectives:

The aim of this review was to evaluate selected molecular tests in diagnosis and screening of cytomegalovirus (CMV) infection in immunosuppressed patients.

Authors' results and conclusions: In haematology and renal transplant patients, all tests had a similar negative predictive value (NPV) (0.976-0.997 and 0.935-0.995, respectively) when used in CMV screening. Polymerase chain reaction single-round (PCR1) is the least expensive molecular test (7.80-13.70 GBP). Commercial tests, NASBA and Amplicor, are both more expensive (22.50-34.70 GBP NASBA; 23.20-29.20 GBP Amplicor). Antigenaemia costs 12.50-27.40 GBP depending on staff grade and batch size. Quantitative PCR (COBAS) is the most expensive at around 50 GBP per sample. No clear link between screening test results and CMV prescribing was detected; clinicians appear to consider screening results in the context of other factors. There was no evidence that the introduction of CMV screening led to reductions in CMV deaths or improved transplant success rates. For cost per positive test result, PCR1 was the most cost-effective screening test on this indicator (renal patients 116 GBP per true positive, haematology patients 518 GBP). Antigenaemia was the least cost-effective screening test (renal patients 643 GBP per true positive, haematology patients 2475 GBP). Cost-effectiveness analysis and cost per 'beneficial result' (as judged by clinicians) confirmed that PCR1 remained the most cost-effective test. Modelling outputs for targeted screening protocols also supported this.

Authors' recommendations: The study findings offer some evidence that a CMV screening regime is more cost-effective than diagnostic testing alone, based on the cost per true positive detected and interim outcome such as changes in patient management. However, the study was unable to demonstrate any benefits in terms of longer term patient outcomes. If CMV screening is introduced, the use of antigenaemia pp65 is clearly less cost-effective than the use of molecular tests. The study identified the optimum test for CMV screening as an in-house molecular test (single-round PCR test). This test was less costly to perform and also resulted in lower costs linked to false positives and negatives than other tests. The in-house, semi-quantitative test was two to three times more cost-effective than the commercial molecular tests assessed; however changes to European Union legislation may mean that it may not be feasible to use in-house tests. The use of targeted screening (limiting CMV screening to high-risk transplants) as opposed to universal screening offers a significant improvement in the cost-effectiveness ratio for haematology transplant patients, but has limited impact in the case of renal transplants. Economic analyses could be expanded to model the cost-effectiveness of more frequent screening tests (as reported nationally), and screening in other 'at risk' groups. Subgroup specific disease groups should be investigated across a larger population to allow more accurate modelling of the impact of CMV screening on disease progression. Further studies of CMV screening programmes should address a range of outcome measures, including patient outcomes.

Authors' methods: Primary research

Project Status: Completed

URL for project: http://www.hta.ac.uk/1074

Year Published: 2006

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: England, United Kingdom

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk

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