Blood Test Could Provide Earlier Diagnosis of Liver Disease

A new "traffic light" test could be used in primary care to diagnose liver fibrosis and cirrhosis in high-risk populations.

Called the Southampton Traffic Light (STL) test, it combines several different tests and clinical markers, which are given a score that indicates the patient's likelihood of developing liver fibrosis and liver cirrhosis.

The STL algorithm combines two serum markers of fibrosis, collagen p3 n peptide (P3NP) and hyaluronic acid (HA), together with platelet count, and can be calculated in two ways: either with a complex exponential function derived from logistic regression analysis, or, alternatively, with a simple clinical rule for the individual test results:
HA >30 μg/L or P3NP >5.5 μg/L–score +1
HA >75 μg/L–score +2
Platelet count <150 × 109/L–score +1
Total score: 0 = green, 1 = amber, 2 or more = red

The “traffic light” aspect refers to grouping of the results of a combination of blood tests into “high risk,” “intermediate risk,” and “low risk” categories in terms of the patients' risk of developing serious liver disease. The results are therefore actually numbers rather than traffic light-colored test tubes etc. The novel part is the grouping together of the individual tests such that their combined predictive value for the presence of liver disease is much greater than the tests when used individually.

The result is interpreted as follows: red means that the patient has liver scarring (fibrosis) and may even have cirrhosis, green means that there is no cirrhosis and the patient is highly unlikely to die from liver disease over the next five years. Amber means 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 more than 1,000 patients and their progress was followed and monitored, in some cases for several years, to assess the accuracy of the test in predicting whether they developed liver fibrosis or cirrhosis. It was accurate in severe liver disease but is not meant to be a substitute for clinical judgment or other liver function tests. However, it can provide family doctors with a means to assess the potential severity of liver fibrosis in high-risk patients such as heavy drinkers, those with type II diabetes, or obese individuals.

Devised by Dr. Nick Sheron and colleagues at University of Southampton (Southampton, United Kingdom) and Southampton General Hospital (Southampton, United Kingdom), details of the test appear in the September 2012 issue of the British Journal of General Practice (BJGP).

Prof. Sir Ian Gilmore, chair of the Alcohol Health Alliance commented, "One of the challenges of liver disease, which is rising dramatically in this country, is the silent nature of the condition until it is often too late to reverse the damage. However, minor changes in standard liver blood tests are so common that it is difficult for GPs to know when to refer for specialist advice. This large study from Dr .Sheron and colleagues in Southampton may prove really useful for guiding the right patients towards specialist care in a timely way."

Related Links:
University of Southampton
Southampton General Hospital