The appearance of blood in a tube from a peripheral blood draw can give a clue to disease. A specimen may demonstrate lipemia (see Fig. 25.62), which is defined as visible turbidity in serum samples due to lipoprotein particles, specifically chylomicrons. The most common cause of lipemia is hypertriglyceridemia.
Hypertriglyceridemia. Grossly lipemic serum sample seen in a patient with a triglyceride level of 9000 causing acute pancreatitis. (Photo contributor: Sarah Monks, MD.)
Methemoglobinemia results in a deep brown color of a peripheral blood draw due to the reduced oxygen-carrying capacity of methemoglobin. The most common cause is drug or toxin exposure. Medications notorious for causing methemoglobinemia include benzocaine, dapsone, amyl nitrite, sulfonamides, chloroquine, metoclopramide, and nitroprusside.
Management and Disposition
Patients with hypertriglyceridemia typically come to the emergency department because of consequences of the disease such as acute pancreatitis, myocardial infarction, or stroke.
Treatment of methemoglobinemia is intravenous methylene blue.
The most common cause of endogenous laboratory interference after hemolysis is lipemia.
Methemoglobin levels of 15% to 30% will cause cyanosis and brown blood.
Methylene blue, the antidote for methemoglobinemia, can cause methemoglobinemia.