The amount of a deoxynucleoside triphosphate triphosphohydrolase SAMHD1 when measured in blood serum. The trait is level of deoxynucleoside triphosphate triphosphohydrolase SAMHD1 in blood serum (Ontology of Biological Attributes id OBA_2043375). Also known as: blood serum deoxynucleoside triphosphate triphosphohydrolase SAMHD1 amount.