Abstract
Discolored serum poses a problem in performing laboratory tests. While impact of hemolytic blood sample imparting reddish appearance, lipemic sample imparting milky, and icteric sample imparting yellow green color to the serum is known on the laboratory tests, we present a rare case of black serum and its effect on hematology, biochemistry, and serological tests. We concluded that it is safe and permissible to run samples with black serum on hematology and biochemistry fully automated auto-analyzers. The hematology and serological tests remained unaffected; however, we suggest that a comment of black discoloration of serum, which may affect the quality of results, should be made for biochemistry analytes.