Orthohantavirus infection is a zoonotic disease transmitted to humans through contact with infected rodents. In Eurasia, Old World Orthohantaviruses can cause haemorrhagic fever with renal syndrome (HFRS), while in the Americas, New World Orthohantaviruses are responsible for hantavirus cardiopulmonary syndrome (HCPS). In Kazakhstan, the first recorded cases of HFRS appeared in the West Kazakhstan region in 2000, which has since then been established as an endemic area due to the presence of stable rodent reservoirs and recurring human infections. Routine diagnosis of HFRS in this region relies primarily on immunoassays. To enhance diagnostic precision, we aimed to implement both serological and molecular methods on samples from suspected HFRS cases in the endemic West Kazakhstan region and non-endemic Almaty City. A total of 139 paired serum, saliva, and urine samples were analysed using IgM/IgG ELISA, immunoblot assays, and qPCR. Our findings confirm that suspected HFRS cases in West Kazakhstan are associated with the Puumala virus serotype.