Efficacy of Different Diagnostic Test for Identifying Wilson's Disease

Wilson disease is an autosomal recessive disorder in which copper pathologically accumulates primarily within the liver, brain and other tissues. It can presents clinically as liver disease, as a progressive neurological disorder or as psychiatric illness. The wide array of clinical manifestations of WD can lead to misdiagnosis with subsequent greater risk of irreversible damage to liver and brain. Many tests can be used to investigate patients of Wilson disease, including serum free copper, 24 hours urine copper estimation, hepatic copper estimation and genetic mutation testing. But there is no single ideal diagnostic test that can exclude or confirm the disease with certainty. The aim of the study was to find out the efficacy of different diagnostic test for the diagnosis of Wilson disease. This cross-sectional analytical study was conducted at department of Paediatric Gastroenterology and Nutrition of Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from January 2016 through January 2018. A total of 56 cases of Wilson disease and 39 patients with a liver disease other than WD were studied. Wilson disease was diagnosed by Leipzig score. Along with other physical findings and laboratory investigations slit lamp eye examination for KF ring, serum ceruloplasmin and 24 hour urinary copper excretion were done. The mean age of WD patients was 9.69±2.37 years, male female ratio was 1:1. Serum ceruloplasmin level was significantly lower in WD patient (p<0.001). Median of 24 hour urinary copper in WD was 702.75μg/ 24 hr (range119-11210μg/24 hour) and in non WD group it was 77.41μg/24 hour (range 20.0-478μg/24 hour) and the difference between them is statistically significant (p=0.001). The sensitivity of KF ring was 82.1% and specificity was 100%. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of serum ceruloplasmin were 98.2%, 92.3%, 94.8%, 97.2% and 95.7% respectively. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 24 hour urinary copper were 100%, 63%, 80% and 85.1% respectively. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of KF ring, serum ceruloplasmin and basal 24 hour urinary copper excretion when combined together came out to be 70.4%, 100%, 100%, 59.3% and 79.3% respectively. This study result showed that serum ceruloplasmin and 24 hour urinary copper can be used as a screening test for the diagnosis of Wilson disease.