Measurement of Midregional Proadrenomedullin in Plasma with an Immunoluminometric Assay

N. G. Morgenthaler
2005 Clinical Chemistry  
Adrenomedullin (ADM) is a potent vasodilatory peptide, and circulating concentrations have been described for several disease states, including dysfunction of the cardiovascular system and sepsis. Reliable quantification has been hampered by the short half-life, the existence of a binding protein, and physical properties. Here we report the technical evaluation of an assay for midregional pro-ADM (MR-proADM) that does not have these problems. Methods: MR-proADM was measured in a sandwich
more » ... uminometric assay using 2 polyclonal antibodies to amino acids 45-92 of proADM. The reference interval was defined in EDTA plasma of 264 healthy individuals (117 male, 147 female), and increased MR-proADM concentrations were found in 95 patients with sepsis and 54 patients with cardiovascular disease. Results: The assay has an analytical detection limit of 0.08 nmol/L, and the interassay CV was <20% for values >0.12 nmol/L. The assay was linear on dilution with undisturbed recovery of the analyte. EDTA-, heparin-, and citrate-plasma samples were stable (<20% loss of analyte) for at least 3 days at room temperature, 14 days at 4°C, and 1 year at ؊20°C. MR-proADM values followed a gaussian distribution in healthy individuals with a mean (SD) of 0.33 (0.07) nmol/L (range, 0.10 -0.64 nmol/L), without significant difference between males or females. The correlation coefficient for MR-proADM vs age was 0.50 (P <0.001). MR-proADM was significantly (P <0.001) increased in patients with cardiovascular disease [median (range), 0.56 (0.08 -3.9) nmol/L] and patients with sepsis [3.7 (0.72-25.4) nmol/L]. Conclusions: MR-proADM is stable in plasma of healthy individuals and patients. MR-proADM mea-surements may be useful for evaluating patients with sepsis, systemic inflammation, or heart failure.
doi:10.1373/clinchem.2005.051110 pmid:16099941 fatcat:6k57g6hjirc5lkhpelumkufsaa