The clinical validation of novel strategies for monitoring transplant recipients

In the early postoperative period after solid organ transplantation, the patient is monitored intensively to detect the early development of surgical and infectious complications or allograft rejection. Laboratory tests form an essential component of the routine monitoring protocol—particularly those that are of diagnostic value in assessing graft function. In this paper, we illustrate how a new liver-function test, α-glutathione S-transferase immunoassay, was subjected to systematic technical and clinical evaluation in the liver-transplant population, including a randomized, controlled trial that provided the evidence for its introduction into the routine laboratory. We also illustrate how the carefully controlled monitoring in a clinical trial is difficult to reproduce under routine circumstances and the crucial role of audit in ensuring that recommendations governing the use of a new diagnostic test are adhered to in clinical practice. Finally, we describe an “equivalence study,” whereby our rigorous validation of the α-glutathione S-transferase assay has enabled us to fast-track the development of a simpler and cheaper liver function test (fructose 1,6-bisphosphatase), which shares similar diagnostic characteristic to α-glutathione S-transferase, without the requirement for a further clinical trial.