Diagnostic accuracy of alpha-fetoprotein at various cut-off levels in hepatocellular carcinoma: A study in a tertiary health care centre, Peshawar.

Objective: To evaluate the diagnostic accuracy of alpha-fetoprotein (AFP) at various cutoff levels in detecting hepatocellular carcinoma (HCC) and to determine the optimal AFP value for HCC diagnosis. Study Design: Cross-sectional study. Setting: Department of Interventional Radiology, Rehman Medial Institute. Period: May 2016 to Dec 2023. Methods: Utilising a dataset of 882 participants, among whom 707 were HCC positive and 175 HCC negative. The values obtained from the AFP measurements were classified into several ranges. Effectiveness of diagnostic test at various AFP cut-off points (10µg/L, 20µg/L, 100µg/L and 200µg/L) were calculated in terms of sensitivity, specificity and positive and negative predictive values. Results: The best sensitivity of 79.5% was obtained through the use of an AFP threshold of ≥10 ng/mL. However, this resulted in the true negative rate of 21.7%. The most sensitive cut-off value was ≥100 ng/mL for 84.2%, and the highest specificity and PPV was obtained in the cut-off at ≥200 ng/mL for 97.1% and 95.4%, respectively. This is because the AFP accuracy is not constant and varies from level, therefore, should be used in combination with other diagnostic tools. Conclusion: It was found that the diagnostic accuracy of AFP is different with different cut-off levels which make it appropriate for either screening or confirming diagnosis in different ways. The low cut-offs are suitable for screening, whereas the high cut-offs fit the purposes of diagnosis confirmation. Studying the correlations and combination of AFP with other diagnostic biomarkers and imaging modalities should be the direction of future studies for HCC diagnostic models.