Liver function tests (LFTs) are frequently requested as part of routine health assessments on serving members of the Royal Navy (RN). In common with many investigations there are a number of abnormal results in healthy individuals (0.5 - 9% depending on test and study population). There are established patterns of LFT derangement such as cholestatic derangement, hepatocellular derangement, and failure of synthetic function. There can be indicators to the cause of the derangement by assessing the ratios of elevated assays in relation to one another. This article aims to address the definition, potential causes and further investigation of common patterns of LFT derangement found in primary care in the RN.