Sorted By Test Name - Mayo Medical Laboratories

ADMA
83651
1 0.35-0.69 Equivocal
2 0.70-3.49 Positive
3 3.50-17.4 Positive
4 17.5-49.9 Strongly positive
5 50.0-99.9 Strongly positive
6 > or =100 Strongly positive Reference values
apply to all ages.
Clinical References: Homburger HA: Allergic diseases. In Clinical Diagnosis and Management by
Laboratory Methods. 21st edition. Edited by McPherson RA, Pincus MR. WB Saunders, Publ, New York,
Chapter 53, Part VI, pp. 961-971, 2007
Asymmetric Dimethylarginine, Plasma
Clinical Information: The conversion of arginine to nitric oxide (NO) is catalyzed by nitric oxide
synthase (NOS), and asymmetric dimethylarginine (ADMA) is an inhibitor of that enzyme. When NO
synthesis is blocked, a number of regulatory processes are immediately affected, including vasodilation,
platelet aggregation, monocyte adhesion, and the inflammatory pathway, amongst others. ADMA has
been of interest in cardiovascular research for several years. Increased baseline plasma ADMA levels
have been reported to be a predictor of outcomes in various studies including: -In patients with acute
coronary syndrome (ACS), 2 year follow up, the hazard ratio (HR) for all-cause mortality and for
myocardial infarction (MI) was 2.45 and 2.28, respectively.(1) HR is the relative risk of an adverse event.
-In diabetics referred for coronary angiography, 2 year follow up, the HR for all-cause mortality and MI
was 2.63 and 2.44, respectively.(2) -In patients with unstable angina, 1 year follow up, ADMA
persistently elevated was associated with increased cardiac events.(3) -In nonsmoking males with a
previous coronary event, 5 year follow up, 4-fold increase in risk of an adverse event.(4) However, other
studies have been inconclusive or found no association with cardiac events. Furthermore, the cardiac
events may be up to 13 years or more in the future. ADMA may be particularly important in assessing
cardiovascular risk in the setting of renal failure. Patients with chronic renal failure have been shown to
have increased ADMA concentrations compared to healthy controls. The elevated ADMA-associated
inhibition of NO has been identified as a potential causal mechanism for the high mortality rates in
patients with end-stage renal disease.(5,6) The literature data must also be assessed with a cautionary eye
to the methodology used, since the inactive isomer, symmetric dimethylarginine (SDMA), can contribute
to the analytical result in some procedures. Our method measures ADMA without interference from
SDMA. It is important to consider the ADMA level in the context of all other biochemical parameters,
whether it is a cardiac risk marker and/or a representation of an underlying disease process itself. The
NOS pathway is involved in many physiological response mechanisms, and the ADMA levels measured
in plasma samples reflect an integration of the contributions from all of them. Combinations of effects can
blunt or reverse the predictive value of ADMA. Other risk factors, notably smoking, alter ADMA levels
in a manner that reduces its predictive value for cardiac outcomes. In one study, ADMA levels were
predictive of coronary events in nonsmokers, but not in smokers, where the levels were considerably
lower. The underlying reason was postulated to be the upregulation of a key ADMA metabolizing enzyme
by tobacco smoke, thus driving the plasma levels down.(7)
Useful For: An adjunct to other risk markers for assessing an individualâ€s overall probabilistic
likelihood of future coronary events, especially in patients with renal failure. This test is best used to aid
in eliciting lifestyle changes that can reduce risk of coronary events; it does not predict absolute events,
nor does it predict specific events.
Interpretation: In patients with pre-existing coronary conditions or at high risk for coronary events
(diabetes, renal insufficiency), asymmetric dimethylarginine (ADMA) levels in the upper tertile, >112
ng/mL, have an increased risk for future coronary events. The arginine value is considered only in some
situations, when amino acid metabolism may be altered. Reductions in ADMA are not known to be
predictive of decreased risk of future coronary effects.
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