Immunoluminometric assay of chromogranin A in serum with commercially available reagents.
Chromogranin A (Cg A) is a useful marker of neuroendocrine neoplasia in humans. Here we describe an immunoluminometric assay (ILMA) for measuring Cg A in serum, with use of a new tube as a solid phase. The new tube has a large surface area and is coated with a polyclonal antibody. Optimized coating conditions provide a high IgG adsorption to the polystyrene wall. Serum is added to the coated tube and incubated for 2 h or overnight. After washing the tubes, acridinium ester-labeled monoclonal antibody against Cg A is added and incubation is continued for 2 h. The tubes are washed again and the bound luminescence is measured. The assay is very sensitive (detection limit 1 microgram/L, if 25 microL of serum is used), is specific for human Cg A, and offers a wide dynamic range (1-1000 micrograms/L). The range in healthy humans is 10-53 micrograms/L (median 30 micrograms/L). The correlation of serum Cg A to creatinine and parathyroid hormone is described. We also report the influence of intravenous calcium injection on Cg A concentrations in serum.
Bender
H
H
Endocrine Laboratory, Heidelberg, FRG.
Maier
A
A
Wiedenmann
B
B
O'Connor
D T
DT
Messner
K
K
Schmidt-Gayk
H
H
D000911:Antibodies, Monoclonal; D002395:Catecholamines / Q000097:blood; D053379:Chromogranin A; D002864:Chromogranins / Q000097:blood*; D003404:Creatinine / Q000097:blood; D004355:Drug Stability; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D007700:Kinetics; D008163:Luminescent Measurements; D010281:Parathyroid Hormone / Q000097:blood; D011863:Radioimmunoassay; D011933:Reagent Kits, Diagnostic; D012016:Reference Values
D000911:Antibodies, Monoclonal; C506150:CHGA protein, human; D002395:Catecholamines; D053379:Chromogranin A; D002864:Chromogranins; D010281:Parathyroid Hormone; D011933:Reagent Kits, Diagnostic; D003404:Creatinine