Table 1.

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.