Ischemia modified Albumin : A concept molecule for rapid diagnosis of ischemia
Posted Sep 04 2010 8:28am
In the diagnosis of ACS, we have definite bio markers for acute MI . Further, ECG has a good spcecificity for STEMI . While ,clinical and ECG features of ischemia are not perfect. A bio marker for ischemia is the ultimate dream of cardiologists and emergency room physicians. . In this context , the IMA -ischemia modifed albumin has come with great expectation .
Ischemia modifies what ?
Normal albumin moleule has a metal binding site (Copper ) .There are few free binding sites available .During ischemia this metal binding capacity reduces . A cobalt containing reagent when added to ischemic blood finds binding sites scarce , and hence excess free cobalt will color the sample and a posiitve test for ischemia is diagnosed.
*Normal human albumin may contain 2% of ischmia modifed albumin which is expected to increase up to 6% during ischemia
IMA raises not only during ischemia it can also raise during oxidative stress
Stroke,
Chronic kidney disease
liver disease,
Maligancy
It can also be elevated following
Routine coronary angiogram
PCI
DC shock
Increased lactic acid for example in sepsis may reduce the IMA level and can miss an episode of true ischemia
Final message
IMA can be a useful tool to identify ischemia early .But lacks senstiivty . New improved immunoassays may be more sensitive and specific
In the diagnosis of ACS, we have definite bio markers for acute MI . Further, ECG has a good spcecificity for STEMI . While ,clinical and ECG features of ischemia are not perfect. A bio marker for ischemia is the ultimate dream of cardiologists and emergency room physicians. . In this context , the IMA -ischemia modifed albumin has come with great expectation .
Ischemia modifies what ?
Normal albumin moleule has a metal binding site (Copper ) .There are few free binding sites available .During ischemia this metal binding capacity reduces . A cobalt containing reagent when added to ischemic blood finds binding sites scarce , and hence excess free cobalt will color the sample and a posiitve test for ischemia is diagnosed.
*Normal human albumin may contain 2% of ischmia modifed albumin which is expected to increase up to 6% during ischemia
IMA raises not only during ischemia it can also raise during oxidative stress
It can also be elevated following
Increased lactic acid for example in sepsis may reduce the IMA level and can miss an episode of true ischemia
Final message
IMA can be a useful tool to identify ischemia early .But lacks senstiivty . New improved immunoassays may be more sensitive and specific
Reference
1 . Medscape review
2. Circulation article
3. PRIMA study which was done in ER in risk stratifying ACS proved IMA is not vey useful http://emj.bmj.com/content/23/10/764.abstract