In a client being evaluated for a suspected primary malignant liver tumor, an elevated **alpha-fetoprotein (AFP) level** would be a laboratory study result that may indicate the possibility of a primary malignant liver tumor.
Alpha-fetoprotein is a tumor marker that can be elevated in certain liver cancers, particularly hepatocellular carcinoma (HCC). Elevated AFP levels are not exclusive to HCC and can also be seen in other conditions, but when found in conjunction with clinical and imaging findings, it raises suspicion for a primary malignant liver tumor.
The other laboratory study results listed (elevated white blood cell count, decreased AST levels, and decreased alkaline phosphatase levels) are generally not specific indicators of a primary malignant liver tumor and may be influenced by various other factors and medical conditions.