Tests Combined for Early Diagnosis of Liver Disease
15 Oct 2012
A recently devised test could be used in primary care to diagnose liver fibrosis and cirrhosis in high-risk populations more easily than at present.
Known as the Southampton traffic light test (STL), it combines the fibrosis markers procollagen-3 N-terminal peptide (P3NP) and hyaluronic acid (HA), along with routine liver function tests in a clinical algorithm that can be used in an outpatient clinic.
Scientists at University of Southampton (UK) studied 1,038 consecutive patients with suspected liver disease, in whom the routine full blood count, liver function tests, and analysis of the serum HA or collagen P3NP had been performed as part of routine diagnosis, between July 2003 and November 2009.
The fibrosis markers were assayed using commercial immunoassays. The assay for P3NP was from Orion Diagnostica (Espoo, Finland) and the HA assay was from Corgenix Inc. (Broomfield, CO, USA). The STL is a clinically derived heuristic, based on the scientists experience using fibrosis markers in the liver clinic. To aid interpretation for the study, the results were categorized into three grades: green, amber, and red, as follows: if the HA is greater than 30 µg/L or P3NP is greater than 5.5 µg/L, this equals a score of plus one. If the HA is greater than 75 µg/L, this equal a score of plus two and a platelet count of less than 150 ×109/L gives a score of plus one.
The red means that the patient had a score of two or more and has liver scarring (fibrosis) and may even have cirrhosis. The green means the score is zero and that there is no cirrhosis and the patient is highly unlikely to die from liver disease over the next five years. The amber means a score of one and there is at least a 50:50 chance of scarring with a significant possibility of death within five years, and patients are advised to stop drinking to avoid further disease and death.
The test was given to over 1,000 patients, and their progress was carefully followed and monitored afterwards, in some cases over several years, to assess the accuracy of the test in predicting whether they developed liver fibrosis or cirrhosis. The test proved to be accurate in severe liver disease, and while not a substitute for clinical judgment or other liver function tests, can provide physicians with an objective means to accurately assess the potential severity of liver fibrosis in high-risk patients, such as heavy drinkers, those with type II diabetes, or obese people.
Nick Sheron, MD, FRCP, the senior author said, "We are reliant on general practitioners detecting liver disease in the community so they can intervene to prevent serious liver problems developing, but so far we haven''t been able to give them the tools they need to do this. We hope that this type of test for liver scarring may start to change this because the earlier we can detect liver disease, the more liver deaths we should be able to prevent." The study was published in September 2012 in the online edition of the British Journal of General Practice (BJGP).