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our hospital uses both CPK and troponin testing- they are talking about serum myoglobin ( but apparently its expensive). According to what I've been told- Troponin levels are more sensitive than CPKs and will be elevated for a longer period of time. If you have a normal CPK and an elevated Troponin-I- they believe the troponin level. I'n sure "Critical Care Nurse" or "Nursing 98" may have something out on it.
In the ED at our hospital they only use troponin testing. If the patient is admitted then the cpk with isoenzymes are done. Usually two sets of cpk's. We also use myoglobin testing which in a sense is silly to me to do all three. But like I said the ED is where it all starts and typically they use troponin and myog.
We started troponins about 9 months ago. They were unsure to the accuracy so, we have been doing CK, CKMB, and Isos. Evidently they found troponins pretty accurate. We don't routinely do all now. For about the last 3 months we only do troponins Q3H x 3 unless other tests are ordered by the MD. So far, so good.
We use troponins all the time and have been since before I started on my floor (over a year). In addition we look at CK/CKMB levels as well. Our cardiologists only use the CKs post-intervention, but when ruling someone out troponins are becoming the gold standard see this article: Troponin Elevation Key Element in Universal Definition of MI
If memory serves, from 0.04ng/ml to 0.49ng/ml serial testing is recommended due to possible myocardial damage, anything greater than 0.50ng/ml is considered myocardial damage.
I have seen false elevations, especially in end-stage renal patients (here's a google search page about this ).
Cheers,
Tom
alvrn
2 Posts
Our hospital recently starting using Troponin levels along with CPK-MB levels to rule out MI's. The problem is that we were not given any inservice into understanding the levels. Are there any conditions that can affect the validity of the testing? Does anyone know where I could get some info on this? Are the results valid if you get a normal CPK-MB but a high Troponin level? Thanks for any info.