Myoglobin is an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the red blood cells. Myoglobin is only found in the bloodstream after muscle injury. It is an abnormal finding, and can be diagnostically relevant when found in blood.
Myoglobin may be ordered as a cardiac biomarker, along with troponin, to help diagnose or rule out a heart attack. Levels of myoglobin start to rise within 2-3 hours of a heart attack or other muscle injury, reach their highest levels within 8-12 hours, and generally fall back to normal within one day. Myoglobin can be used for ruling out AMI in the emergency room, from 3 until 6 hours after the onset of symptoms.
Myoglobin was the earliest marker, and its negative predictive value (NPV) was significantly higher than for other markers from 3 to 6 hours after the onset of symptoms.
In a set of survey samples using SDi CX against SIEMENS Centaur give the following correlation:
y = 0.9092x – 8.8934
R² = 0.9839