Correlation between serological tests and radiological imaging in the diagnosis of hydatid disease

Hydatid disease (HD) is a zoonotic parasitic infection caused by the larval stage of Echinococcus granulosus. It remains a major public health issue in many countries, including Türkiye. Diagnosis relies on clinical findings, serological tests, and radiological methods. This study aimed to investigate the relationship between the indirect hemagglutination (IHA) test and radiological imaging in suspected HD cases. In this retrospective study, patients with suspected HD between July 2023 and June 2024 were included. Serum samples were tested using the IHA method, and ultrasonography (US), computed tomography (CT), or magnetic resonance imaging (MRI) was performed within 15 days for seropositive patients. The association between IHA titers and cyst size, localization, and the number of affected organs was analyzed. The study included 1289 cases, and seropositivity was detected in 147 (11.4%) of these cases. Seropositivity was higher in men (12.3%) than in women (10.7%). The majority of cases were in the 41-60 age group (43.5%). US was the most frequently used radiological imaging method, and the most common cyst location was the liver (91.95%). Although descriptive differences in cyst diameters were observed across different IHA titer levels, no statistically significant correlation was identified. These results indicate that IHA titers do not reliably reflect cyst size, disease extent, or radiological severity. Therefore, serological findings should not be interpreted as indicators of disease burden and must be evaluated strictly in conjunction with radiological imaging in the diagnosis, staging, and follow-up of hydatid disease.