Changes in recommendations - Biochemical Markers
2014 Guideline			2020 Guideline
Biomarkers of myocardial necrosis should be measured in all patients suspected of having non-ST-elevation acute coronary syndromes (NSTE-ACS). The markers should be measured at admission and repeated at least once 6 to 9 hours (preferably 9 to 12 hours) after symptom onset if the first dosage is normal or slightly elevated.	I	C	Biomarkers of myocardial necrosis should be measured in all patients with suspected NSTE-ACS. When highly sensitive troponin assays are available, serum levels should be measured at admission and, ideally, reassessed in 1 h or up to 2 h. If unavailable, conventional troponin measurement should be performed at admission and repeated at least once, 3 to 6 hours later, if the initial results are normal or slightly elevated.	I	B
Creatine kinase-MB (CK-MB) mass and troponins are the biochemical markers of choice.	I	A	CK-MB mass levels can be used if troponin levels are not available.	IIb	B
For patients who arrive early at the emergency department (6 h prior to symptom onset), myoglobin and highly sensitive troponin may be considered in addition to a later marker (CK-MB or troponin).	IIb	B	Troponins are the biomarkers of choice in patients with suspected AMI.	I	A
			Myoglobin can be used to detect myocardial necrosis in patients with suspected NSTE-ACS.	III