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Abstract
Introduction:
Choledocholithiasis is an important medical condition linked to gallstone formation and can cause severe medical problems if not detected early enough. While liver function tests, especially ALP, are commonly used as initial screening tools, there are doubts about their diagnostic accuracy, especially where resources are limited.
Objective:
To evaluate the diagnostic utility, particularly the positive predictive value, of raised serum alkaline phosphatase in predicting choledocholithiasis using intraoperative findings as the gold standard.
Methods:
The present descriptive cross-sectional study was conducted in a tertiary care hospital during six months and included 139 patients of symptomatic gallstone disease who underwent laparoscopic cholecystectomy. The pre-operative serum levels of ALP were noted, and values higher than 400 IU/L were classified as high. Intraoperative findings were taken as the gold standard to detect the CBD stones. Various diagnostic indices such as sensitivity, specificity, PPV, NPV, and accuracy were obtained using a 2 × 2 contingency table. The Fisher’s exact test was used to analyse the associations.
Results:
The average age of the respondents was 46.3 ± 14.9 years, with women accounting for 66.2% of the sample. The prevalence rate of CBD stones was 13.7%. An increase in ALP levels was noted in 96.4% of cases. The sensitivity level of ALP in diagnosing CBD stones was very high (89.5%, 95% CI: 66.9–98.7%), whereas the specificity level was extremely low (2.5%, 95% CI: 0.5–7.1%). The PPV and NPV were 12.7% (95% CI: 7.6–19.5%) and 60.0% (95% CI: 14.7–94.7%), respectively, giving an overall diagnostic accuracy of 14.4%. There was no significant relationship between elevated ALP levels and CBD stones (p = 0.138). However, subgroup analysis revealed that there was no significant relationship.
Conclusion:
Even though increased ALP shows high sensitivity, the fact that the method lacks specificity and predictive value makes it impossible to be used alone for the diagnosis of choledocholithiasis. This suggests the necessity to conduct diagnostics on the basis of a combination of various methods.