Myoglobin

Casandra

Casandra Test Code LC39055Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 010405CPT Code 83874

Clinical Use

Use

Diagnose skeletal or myocardial muscle injury. Serum myoglobin is generally detectable earlier than is CK or CK-MB increase in patients with acute myocardial infarction.1 Serum myoglobin was found also in 50% of patients with acute coronary insufficiency. It is thought to define a population of small infarcts of myocardium. It correlates with size of infarct.1 Diagnose rhabdomyolysis.2 Myoglobin appears with trauma, ischemia, malignant hyperthermia, exertion, dermatomyositis, polymyositis, and muscular dystrophy.3

Special Instructions

This test may exhibit interference if the sample is collected from a person consuming a supplement with a high dose of biotin (vitamin B7/B8, vitamin H, or coenzyme R). Patients should be asked about biotin supplementation and are advised to stop biotin consumption at least 72 hours before sample collection.

Limitations

The test lacks specificity for diagnosing acute myocardial infarction, as increased myoglobin levels can occur after intramuscular injections. Increased serum myoglobin has been reported after high voltage electrical accidents. As a myocardial infarct index, myoglobin levels rapidly return to baseline. Serum myoglobin is rapidly cleared by the kidneys, and urine myoglobin levels are not detected after a myocardial infarct. Elevated levels may be associated with cocaine abuse. Other causes of elevated serum myoglobin include open heart surgery, exercise, progressive muscular dystrophy, shock, and renal failure. It is increased in azotemic subjects and not affected by dialysis.

Test Details