Causes
Clinical
features
Investigations
Therapy
Prognosis
|  | | | Investigations |
-
myoglobin c
Why?
An elevated myoglobin diagnoses an MI, but
normal levels cannot safely rule it out
| Patient c
|
Target Disorder and
Reference Standard |
Diagnostic Test |
LR+
(95% CI)
|
Post-test Probability |
LR-
(95% CI)
|
Post-test Probability |
suspected myocardial infarction
(pre-test probability: 18%)
|
myocardial infarction
(history, ECG, CK-MB
act
)
|
elevated
myoglobin
at 3 hours after symptom onset
|
34
(23 to 49)
|
88% |
0.33
(0.28 to 0.38)
|
7% |
|
|
|
at 4 hours
|
26
(17 to 38)
|
85% |
0.24
(0.20 to 0.28)
|
5% |
|
|
|
at 6 hours
|
26
(17 to 39)
|
85% |
0.23
(0.19 to 0.27)
|
5% |
|
|
|
at 8 hours
|
25
(17 to 36)
|
85% |
0.26
(0.22 to 0.30)
|
5% |
|
|
|
at 12 hours
|
23
(16 to 31)
|
83% |
0.33
(0.28 to 0.39)
|
7% |
|
|
|
at 20 hours
|
13
(8 to 20)
|
74% |
0.63
(0.56 to 0.71)
|
12% |
Normal CK-MB and troponin I can help rule out MI
| Patient c
|
Target Disorder and
Reference Standard |
Diagnostic Test |
LR+
(95% CI)
|
Post-test Probability |
LR-
(95% CI)
|
Post-test Probability |
chest pain lasting for at least 15 minutes within previous 24 hours
(pre-test probability: 37%)
|
myocardial infarction
(CK-MBmass at 24 hours)
|
troponin I at 6 hours
|
10
(7.3 to 14)
|
59% |
0.45
(0.37 to 0.56)
|
6% |
|
|
|
at 18 hours
|
15
(11 to 19)
|
67% |
0.045
(0.019 to 0.11)
|
1% |
|
internal medicine