Initially when blood levels of troponin T and I were found to
be raised in patients suffering from myocardial infarct, the clinicians
(specially family physicians) were very happy to get help from
a blood test (rather than a cardiologist only), to diagnose a cardiac
emergency. What followed is that the importance of troponin levels
is now in the textbooks! But troponin levels got so much importance
that the terminologies of `unstable angina' and `myocardial infarction" were
changed. “Acute Coronary Syndrome” was the new label
given to all patients having chest pain with any ECG changes and
increased Troponin levels.
As time passed it was realised that there
are more than a dozen conditions where Troponin levels can rise
including serious hospital
patients and even those having Pulmonary Embolism!! At present,
the value of this test is that at the end of 12 hours, if the
troponin levels are normal, acute coronary syndrome can be excluded
by a family physician. So the value of a negative test has become
more important.
The history of D'Dimer seems to be repeating like
that of Troponin. Initially, we were happy that we have found a
blood test to diagnose
Pulmonary Embolism. Then followed a number of reports that D'Dimer
blood levels were also elevated in deep vein thrombosis, DIC,
renal, liver and cardiac failure, major injuries and surgeries,
etc.
Srinivas et al on page 290 of this issue report elevated
levels in patients of prostatic cancer, before and even after
the operation.
This seems to be the first report in world literature. If similar
reports continue to pour in, the family physicians will be left
with only one lesson to learn - that a negative D'Dimer excludes
Pulmonary Embolism. However, a positive D-dimer test does not
do so. This calls for looking out for many other conditions which
can raise D'Dimer levels. |
