Multiple commonly occurring compounds that naturally fluoresce can comigrate with CK-BB and CK-MB during electrophoresis; some of these compounds include bilirubin, aspirin, antidepressants, and benzodiazepines when in high concentrations. CK-MB elevation was used as one of the criteria for diagnosing acute MI; as its use increased in frequency in the late s and s, it became evident that despite its high sensitivity in detecting Acute MI, the specificity of CK-MB activity was low. CK-MB mass measurements using Immunoenzymometryic assays containing monoclonal antibodies binding to M and B subunits individually were proven to be highly specific and more sensitive than CK-MB activity measurement.
According to the Universal consensus statement from the American College of Cardiology and the European Society of Cardiology, acute MI is defined by the presence of at least one of the below criteria. CK-MB concentration gradually rises in blood in 4 to 6 hours after onset of chest pain, peaks by around 24 hours, and returns rapidly to baseline in 48 hours. However, by the time of the joint statement from ACC and ESC in , troponin T testing was proven to be more specific to the myocardium, and it will be discussed briefly later in the article.
As discussed above, the skeletal muscle and myocardial cell death of any etiology will cause an elevation of CK-MB. Listed below are multiple other causes of CK-MB elevation in plasma. False elevations in CK-MB occur in the presence of atypical CK isoforms, macrokinases, and adenylate kinase; however, these false elevations can be eliminated by adding reagents to testing kits.
Cardiac etiology - myocarditis, cardiac surgery can damage heart muscle resulting in elevation of CK-MB. Peripheral sources - rhabdomyolysis, myositis, inflammatory myopathies, trauma, medications daptomycin, statins, antiretrovirals. However, prior studies in patients with trauma and patients with chronic skeletal muscle abnormalities have demonstrated the failure of CK-MB Relative index in differentiating skeletal muscle sources of CK-MB from myocardial cell death.
Miscellaneous causes include hypothyroidism, renal failure, alcohol intoxication, pregnancy, and certain types of malignancies. As explained earlier, following the WHO Criteria for diagnosis of AMI, multiple cardiac biomarkers were being used to diagnose acute myocardial infarction, among them, CK-MB was being used as the most sensitive and specific marker for diagnosis of AMI, detection of reperfusion, and estimating the size of myocardial infarction in the s.
During this time, troponin was evaluated as potentially a more specific biomarker for myocardial infarction when compared to CK-MB. Troponin is a protein complex of 3 units, troponin T, troponin I, and troponin C, present in the actin filament of the skeletal and myocardial muscle cells.
There are multiple isoforms of troponin T and troponin I, one of which is specific to cardiac muscle, and it is not expressed in adult skeletal muscle allowing the development of assays to measure its level in plasma. In the event of myocardial damage, the unbound troponin is first released [22] [23]. The rest of the troponin, which is bound to the actin, is released slowly with structural damage and results in the prolonged duration of elevated troponins in the plasma.
Troponin concentration begins to rise 4 to 6 hours after onset of symptoms, peaks by about 18 to 24 hours, and remains in the detectable levels for 72 to 96 hours. Troponin is more specific to the cardiac muscle when compared to CKMB, and current assays for troponin are more sensitive and specific than the assays for CK-MB measurement.
Given the expression of CK-MB in skeletal muscle and the presence of evidence proving the failure of CK-MB relative index and several other non-AMI causes of CK-MB elevation, troponin has been proven as the biomarker of choice for the detection of myocardial damage of any etiology.
Troponin remains in circulation for a longer duration when compared to CK-MB. However, after the advent of troponin and the current aggressive interventional approach to AMI, and due to lack of literature comparing CK-MB against troponin in the diagnosis of reinfarction, the use of CK-MB has declined.
Given the significant number of studies and guidelines from the American College of Cardiology recommending the use of troponin for the diagnosis and ruling out of acute coronary syndromes instead of CK-MB, decreasing the use of CK-MB in hospital and outpatient setting requires an interprofessional team of healthcare professionals that includes a nurse, laboratory technologists, pharmacist and several physicians in different specialties especially cardiologists and cardiothoracic surgeons.
Specialty-trained nurses are involved in the ordering and interpretation of this test. Clinica chimica acta; international journal of clinical chemistry.
Biochemical and biophysical research communications. Recommendations based on a quantitative analysis. Annals of internal medicine. Clinical chemistry. These include:. This is an infection and inflammation of the heart muscle.
This an infection and inflammation of the thin sac that surrounds the heart. Higher levels may also be caused by muscle damage elsewhere in your body, by diseases that affect your muscles, and by trauma to your chest. The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. Having a blood test with a needle has some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain.
Afterward, the site may be sore. Timing is important. If you have the test too soon after a heart attack, you may have a false-negative result.
You don't need to prepare for this test. Tell your healthcare provider about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use. Search Encyclopedia. CK-MB What is this test? Why do I need this test? Symptoms of a heart attack often include: Pain or discomfort in the chest, such as a squeezing sensation or feeling of fullness Pain in the neck, back, left arm, or jaw Shortness of breath Lightheadedness or dizziness Nausea or vomiting Sudden sweating Tiredness What other tests might I have along with this test?
What do my test results mean? These include: Myocarditis. Higher levels of CK-MB may also mean more of the heart was damaged in the attack. How is this test done? Does this test pose any risks? What might affect my test results? Strenuous exercise and cocaine use can also affect your results.
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