Incidence and Amount of Turbidity, Hemolysis, and Icterus in Serum From Outpatients

Two thousand six hundred consecutive blood specimens submitted to our outpatient chemistry laboratory were graded for lipemia or hemolysis by comparing each specimen to a series of serum samples adulterated with increasing concentrations of lipid emulsion or hemolysate. Icteric specimens were identified but not graded. After visual assessment, the true concentration of triglycerides, hemoglobin, or bilirubin was measured. Two hundred fifty-two specimens (9.7%) from outpatients were identified as having greater than 1+ interferent concentration. Results were as follows: lipemia, 7.5%; hemolysis, 1.6%; and icterus, 0.5%. Visual grading of specimens was not reliable. Since lipemia, hemolysis, and icterus occur frequently in specimens from outpatients, the effect of these potential interferents on analytical results must be considered when choosing an analyzer for the outpatient laboratory.