Components of the MACS decision rule
| Variable | Format |
| a. High-sensitivity cardiac troponin T (ng/L) | Continuous variable |
| b. Heart type fatty acid binding protein (ng/mL) | Continuous variable |
| c. Acute ECG ischaemia (treating clinician’s interpretation) | Dichotomous |
| d. Sweating observed by the treating clinician | Dichotomous |
| e. Vomiting in association with the presenting symptoms | Dichotomous |
| f. Systolic BP <100 mm Hg on arrival | Dichotomous |
| g. Worsening (or crescendo) angina | Dichotomous |
| h. Pain radiating to the right arm or shoulder | Dichotomous |
The MACS rule estimates the probability (p) of acute coronary syndromes as follows (rounded values are presented): p=1/(1+e-(0.068a + (0.17(b -0.28)/1.35) + 1.75c + 1.85d + 1.72e + 1.46f + 0.92g + 0.87h -4.83)). For dichotomous variables, a value of ‘1’ is entered for ‘yes’ and ‘0’ for ‘no’. The constants presented here assume use of the Roche Elecsys hs-cTnT assay and the Randox Laboratories immunoturbidimetric H-FABP assay.
H-FABP, heart type fatty acid binding protein; hs-cTnT, high sensitivity cardiac troponin T; MACS, Manchester Acute Coronary Syndrome.