Enzyme immunoassay for serum dexamethasone using 4-(carboxymethylthio)dexamethasone as a new hapten.
A sensitive and simple enzyme immunoassay for direct quantitation of serum dexamethasone was established. An antiserum with high specificity was produced by the immunization of rabbits with a newly synthesized 4-(carboxymethylthio)dexamethasone-bovine serum albumin conjugate. Alkaline phosphatase was used as a labeling enzyme. The minimum amount of dexamethasone detected was 2 pg per tube on the basis of B/Bo 100 - 2 SD (%) of standard curve. However, taking into account the cross-reaction with steroids such as cortisol in dexamethasone-free serum, the measurable range was from approximately 0.13 to 10 micrograms/dl. Intra- and interassay coefficients of variation were 1.5 - 5.4% and 0.6 - 6.5%, respectively. Serum levels of dexamethasone and cortisol in four normal subjects after an oral administration of 1 mg of dexamethasone are also reported.
Nishiguchi
Y
Y
Clinical Chemistry Laboratory, Kobe Women's College of Pharmacy, Japan.
Kobayashi
Y
Y
Tagawa
N
N
Miyai
K
K
Watanabe
F
F
D000818:Animals; D003429:Cross Reactions; D003907:Dexamethasone / Q000031:analogs & derivatives* / Q000097:blood* / Q000737:chemistry / Q000276:immunology; D005260:Female; D006241:Haptens; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007124:Immunoenzyme Techniques; D008297:Male; D011817:Rabbits; D012680:Sensitivity and Specificity; D012710:Serum Albumin, Bovine
D006241:Haptens; C067202:4-(carboxymethylthio)dexamethasone; D012710:Serum Albumin, Bovine; D003907:Dexamethasone; D006854:Hydrocortisone