Heart Fatty Acid Binding Protein and cardiac troponin: development of an optimal rule-out strategy for acute myocardial infarction

Table 5 Subgroup Analyses Performance of H-FABP with hs-cTn and ECG according to duration from symptom onset to sample collection

Hours from onset of symptoms to sample collection	Proportion of patients with documented date and time of symptom onset, n (%)	Optimal combination^a : ECG positive or hs-cTnI ≥10 ng/L or H-FABP ≥4.3 ng/mL		Optimal combination^a : ECG positive or hs-cTnT ≥7.6 ng/L or H-FABP ≥3.9 ng/mL
Hours from onset of symptoms to sample collection		Sensitivity (%)	Proportion Negative Test Patients^b	Sensitivity (%)	Proportion Negative Test Patients^c
<3 h	215 (21)	100.0 (96.0 to 100.0)	43.3 %	100.0 (96.0 to 100.0)	34.4 %
3–6 h	273 (27)	100.0 (93.7 to 100.0)	43.2 %	98.2 (90.7 to 99.7)	34.4 %
>6 h	528 (52)	98.7 (95.3 to 99.6)	38.4 %	99.3 (96.3–99.9)	30.3 %

^aStrategy that yielded the maximum proportion of low-risk patients whilst maintaining a minimum sensitivity for AMI of 99 %
^bP-value is 0.30 for comparison of proportion of negative test patients between subgroups (chi-square analysis)
^cP-value is 0.37 for comparison of proportion of negative test patients between subgroups (chi-square analysis)

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