Factitious methemoglobinemia caused by hyperlipemia.

Hyperlipemia in an acyanotic patient with diabetic ketoacidosis, alcoholism, and pancreatitis produced a falsely elevated concentration of methemoglobin (19 percent) and a lower-than-expected oxygen saturation measured with an automated spectrophotometer (IL-282 CO-Oximeter). In addition, there was a "normal" hemoglobin level despite a low hematocrit reading. In vitro studies showed that hyperlipemia corresponding to triglyceride levels of 500 mg/100 ml and greater produced erroneously high values for methemoglobin and total hemoglobin and "negative" values for carboxyhemoglobin. These abnormalities disappeared when the excessive lipids were removed by washing the erythrocytes in physiologic saline solution.