Table 3

Test Characteristics of the Marburg Heart Score and the FP Assessment

Variable	ACS	No ACS	Total
MHS using a cut-off value of ≤2
MHS >2	27	84	111
MHS ≤2	9	66	75
Total	36	150	186

Sensitivity: 75.0% (95% CI, 57.5-87.3)	Incidence ACS: 19.4% (95% CI, 14.1-25.9)
Specificity: 44.0% (95% CI, 36.0-52.3)	Incidence No ACS: 80.6% (95% CI, 74.1-85.9)
PPV: 24.3% (95% CI, 16.9-33.6)	OR: 2.36 (95% CI, 1.04-5.35)
NPV: 88.0% (95% CI, 78.0-94.0)	χ²: 0.04

MHS using a cut-off value of ≤1
MHS >1	34	126	160
MHS ≤1	2	24	26
Total	36	150	186

Sensitivity: 94.4% (95% CI, 80.0-99.0)	Incidence ACS: 19.4% (95% CI, 14.1-25.9)
Specificity: 16.0% (95% CI, 10.7-23.1)	Incidence No ACS: 80.6% (95% CI, 74.1-85.9)
PPV: 21.3% (95% CI, 15.4-28.6)	OR: 3.24 (95% CI, 0.73-14.39)
NPV: 92.3% (95% CI, 73.4-98.7)	χ²: 0.11

FP probability assessment using a cut-off value of ≤5
FP probability assessment high (>5)	39	116	155
FP probability assessment low (≤5)	6	82	88
Total	45	198	243

Sensitivity: 86.7% (95% CI, 72.5-94.5)	Incidence ACS: 18.5% (95% CI, 14.0-24.1)
Specificity: 41.4% (95% CI, 34.5-48.6)	Incidence No ACS: 81.5% (95% CI, 75.9-86.0)
PPV: 25.2% (95% CI, 18.7-32.9)	OR: 4.60 (95% CI, 1.86-11.36)
NPV: 93.2% (95% CI, 85.2-97.2)	χ²: <0.01

Combined approach using the MHS and the FP assessments of probability
MHS + FP probability assessment, 1-2^a	36	115	151
MHS + FP probability assessment, 0^b	0	35	35
Total	36	150	186

Sensitivity: 100% (95% CI, 88.0-100)	Incidence ACS: 19.4% (95% CI, 14.1-25.9)
Specificity: 23.3% (95% CI, 17.0-31.1)	Incidence No ACS: 80.6% (95% CI, 74.1-85.9)
PPV: 23.8% (95% CI, 17.5-31.6)
NPV: 100% (95% CI, 87.7-100)

ACS = acute coronary syndrome; FP = family physician; MHS = Marburg Heart Score; NPV = negative predictive value; OR = odds ratio; PPV = positive predictive value.
↵a Either the MHS, the FP assessment, or both were positive using an MHS cut-off value of ≤2 and an FP assessment cut-off value of ≤5.
↵b Both the MHS and the FP assessments were negative.