P60 What does a ‘normal’ LFT really mean?

<h3>Introduction</h3> The incidence of chronic liver disease (CLD) is increasing more rapidly in the UK than in any other European country¹ and is already one of the leading causes of premature mortality.² Early detection is challenging, as symptoms often appear only in advanced stages. When CLD is suspected, the Liver Function Test (LFT) remains the initial test of choice, with little consideration of how to interpret a ‘normal’ result. <h3>Aim</h3> Identify proportion of normal LFTs in a known cirrhotic population. <h3>Method</h3> The departmental cirrhosis database contains 563 patients with confirmed cirrhosis. The LFT (bilirubin, albumin, ALT, ALP), FBC, AST, INR, patient demographics, Child-Pugh status and any clinical correlates (bleeding varices, ascites, encephalopathy) were recorded on 147 randomly selected patients. One-sample t-test performed, comparing the mean values of each parameter to the upper limit of the laboratory normal ranges (and lower limit for the albumin), with effect sizes measured using Cohen’s d and Hedges’ correction for standardization and cross-metric comparison. <h3>Results</h3> 48 cirrhotic patients (31.2%) had normal LFTs (nLFTS), 84 (57.1%) normal platelet count, 33 (22.4%) normal INR and 100 (68.0%) with no clinical correlates (Child-Pugh A). For those without any clinical correlates, the proportion of nLFTs rose to 44 (44%). The AST:ALT ratio calculated for 68 patients (where AST available) was 1.5, and for those with nLFTs, was 1.29. The ALBI score was normal in 87 (59.1%) of entire cohort, and 40 (83.3%) the nLFT cohort. Bleeding varices correlated significantly with platelet count (r = 0.215, p = 0.009) and AST (r = 0.379, p = 0.001). Of the 48 nLFTs, ALBI score [(log10 bilirubin x0.66) + (albumin x -0.085) was -2.98 compared to -2.42 for the cohort. Table 1 shows each parameter’s mean, standard deviation, standard error of mean (SEM) and t value. <h3>Conclusion</h3> Almost one third of cirrhotic patients have normal LFTs. In the entire cirrhosis cohort, albumin and platelet count showed the highest clinical utility. These parameters demonstrate substantial deviations from the mean value, making them powerful markers for liver disease, but these parameters were only abnormal in 23 (15.6%) patients. To our knowledge, validating LFTs against a cirrhotic population is a novel concept, which has revealed impactful insights. These findings are consistent with recent NICE guidance advice against the use of routine liver function tests to rule out cirrhosis³ because a normal LFT can neither rule out nor rule in significant liver disease. <h3>References</h3> Public Health England. Liver disease: applying All Our Health. 2020. [online] GOV.UK. Available at: https://www.gov.uk/government/publications/liver-disease-applying-all-our-health/liver-disease-applying-all-our-health. Williams R, Alexander G, Armstrong I, Baker A, Bhala N, Camps-Walsh G, Cramp ME, de Lusignan S, Day N, Dhawan A, Dillon J, Drummond C, Dyson J, Foster G, Gilmore I, Hudson M, Kelly D, Langford A, McDougall N, Meier P. 2018 Disease burden and costs from excess alcohol consumption, obesity, and viral hepatitis: fourth report of the lancet standing commission on liver disease in the UK. <i>The Lancet</i>. 2018;<b>391</b>(10125):1097–1107. doi:https://doi.org/10.1016/s0140-6736(17)32866-0. NICE (2016). Recommendations | Cirrhosis in over 16s: assessment and management | Guidance | NICE. [online] www.nice.org.uk. Available at: https://www.nice.org.uk/guidance/ng50/chapter/Recommendations#diagnosis.