Blood Tests for Heart Problems

There are multiple blood tests for heart problems to distinguish what, if any, heart condition a person has. Blood tests can also help determine the severity of a disease. These tests are generally done if a patient is exhibiting cardiac distress symptoms in a doctor's office or emergency room.

Troponins

Troponins are tested to determine if a person has suffered from a heart attack or heart muscle injury. Cardiac-specific Troponin I and Troponin T tests are performed upon patients with chest pain and discomfort when entering the emergency room as well as 6 and 12 hours later. Cardiac troponin levels are generally too low to be measured. Any elevation can indicate damage to the heart. High levels indicate that the patient had a heart attack and can remain high for one to two weeks after the incident.

CK-MB and Total CK

CK-MB and total CK are used to determine if a patient has had a heart attack. Total CK alone determines whether there is damage to the heart. CK-MB helps distinguish the source of damage. CK-MB can also help the doctor determine if medication to dissolve any clots has worked. High levels of CK-MB can be determined three to four hours after the chest pain starts and peaks around 18 to 24 hours.

Myoglobin

Myoglobin is a cardiac biomarker that is tested alongside troponin to determine if a patient has had a heart attack. Myoglobin levels can be tested two to three hours after onset of pain, peak around 8 to 12 hours and are back to normal a day later. Myoglobin can be elevated from levels in skeletal muscle as well, which is why it is not tested alone. Negative myoglobin rules out a heart attack and a positive myoglobin indicates confirmation of troponin.

BNP and NT-proBNP

BNP and NT-proBNP test for heart failure severity. Symptoms indicating the need to test for heart failure include leg edema, difficulty breathing, shortness of breath and fatigue. BNP and NT-proBNP help differentiate heart failure from other conditions like lung disease. BNP and NT-proBNP levels can be decreased by beta blockers, diuretics and ACE inhibitors. BNP and NT-proBNP levels can be elevated by increased age and kidney disease.

Additional Tests

Doctors may order additional tests when testing for heart problems. Blood gases can be checked to examine oxygen, carbon dioxide and pH levels. A complete metabolic panel (CMP) tests organ functions. A complete blood count (CBC) checks for anemia and cell balance. Electrolytes balance is tested as well. These blood tests are generally done alongside a history, physical examination, electrocardiograms (EKG), X-rays, stress tests, CT scans, MRI scans, PET scans and ultrasounds.

References

• Heart Disease; Lab Tests Online; August 2009
• The Duke Encyclopedia of New Medicine; The Center for Integrative Medicine at Duke University; 2006