How is traponin I and Traponin t measured?

Question

sorry troponin I and troponin t-
what is the difference?

Answer 1

Loving_Heart - I see that you are a doctor, but it doesn't sound like you're a cardiologist? Troponin-I and troponin-T are two of the proteins that form the muscle apparatus within muscle cells that allow them to contract. ( http://gilead.org.il/hcm/sarcomere.jpg )

Since these proteins reside within the muscle cells, they are not normally found in the blood. When there is injury to heart muscle, the cells that have died basically disintegrate and release these proteins into the bloodstream where they can be detected. Loving_Heart accurately describes the method used to detect these proteins. Once a sample of the blood is obtained and bound to a substrate, special fluorescent antibodies designed to bind to troponin are introduced. The antibodies are then washed away, but any antibodies that have bound to troponin stay behind. Then machines are used to detect the amount of fluorescence that is left. More fluorescence means more antibodies which means there was more troponin in the sample.

Troponin I and Troponin T are different proteins, but there is very little difference in they way they are tested or in the way the tests are interpreted. Troponin I does NOT become immediately positive. Both troponin I and troponin T become positive 4-6 hours after injury, hit their peak at 12-24 hours after injury, and then take a week or more to completely go away.

Here is a graph showing the various tests we use to look for heart muscle injury and when they become positive and peak, etc. ( http://path.upmc.edu/cases/case178/images/micro.JPG ) Myoglobin looks GREAT because it peaks earliest, but it is considered a "nonspecific" test because there are many things other than heart muscle damage that will make it become positive. Troponin (both I and T), even though it takes longer to become positive, is more specific for heart damage. Not many things besides heart muscle injury will cause a troponin to become positive.

I repeat: Trop I does NOT become positive immediately after injury. We are still looking for the perfect test that becomes positive immediately and is 100% specific for heart muscle injury. Hope that clarifies things.

Answer 2

These articles I have searched out for you, will help you a great deal:

The cardiac reader is a system for quantitative bedside determinations of myoglobin (CARDIAC M) and troponin T (CARDIAC T quantitative).
The cardiac reader is a camera with a charged coupled device that optically records the reflectance signal from the detection zone of the immunochemical test strip. Signal and control lines are identified by a pattern recognition algorithm. The intensity of the signal line is proportional to the concentration of the analytes troponin T and myoglobin. The optical signal is converted into concentration via lot-specific calibration curve which is stored in a code chip.
The test require a 150 μl sample of heparinized blood and the reaction times are approximately 8 min for myoglobin and approximately 12 min for troponin T determination. (10)
• For CARDIAC T Quantitative the quantitative measurement range is 0.1 to 3μl troponin T; the display shows values below 0.05 μl as «negative», values between 0.05 and 0.1 μl as «low» and values above 3.0 μl as «high».

Tropinin I.
As with patients administered glycoprotein-IIb/IIIa receptor antagonists, significant reductions in death and MI were seen in unstable angina patients with non-ST segment elevation ACS and negative creatine kinase-MB levels and identified as highrisk by elevated cTnI levels who were subsequently treated with enoxaparin (Lovenox, Aventis).31 Elevated cTnI values (>0.1 µg/mL) during the first 24 hours were strongly associated with a higher risk of death or MI at 48 hours (3.9% vs. 0%; p = 0.01) and at 14 days (13.9% vs. 2.2%; pÜ 0.0001). Elevated cTnI also correlated with higher risk of recurrent ischemia requiring urgent revascularization by 48 hours (10.0% vs. 1.7%; p = 0.001) and 14 days (20.6% vs. 5.6%; p Ü 0.0001). Similar results were demonstrated in the FRISC trial 32 using dalteparin (Fragmin, Pharmacia) treatment. These results support previous studies demonstrating the prognostic utility of cTnI in patients with non-ST segment elevation ACS with no elevation in creatine kinase-MB. cTnI identifies patients at higher risk for early, adverse cardiac events, including severe recurrent ischemia.25,33–35.

THE DIFFERENCE:
Trop I is a sensitive indicator and becomes IMMEDIATELY positive once myocardial damage has occured.
Where as in Trop T results is positive after 4 to 6 hours of myocardial damage.