Avidin-biotin enzyme immunoassay of osteocalcin in serum or plasma.
We describe a competitive enzyme immunoassay, the ExtrAvidin-biotin system, for determining osteocalcin in human serum or plasma. Antibodies were raised against bovine osteocalcin. Binding of the antibodies to osteocalcin was calcium-dependent. Limit of detection is 0.07 nmol/L (0.4 microgram/L). The standard curve for method is linear between 0.3 and 17.6 nmol/L (1.9 and 100 micrograms/L). Interassay CV over the range 0.9 to 14.8 nmol/L (5.3 to 84 micrograms/L) is 7.5% to 11.7%. Analytical recovery is 105% +/- 5% (mean +/- SD). The measurement, which is adapted to microtiter plates, requires only 20 microL of serum and 5 h. The coefficient of correlation between the concentrations measured by this method and by a commercially available radioimmunoassay kit (CIS Biointernational) is 0.91. Osteocalcin can be measured in serum or heparinized plasma. Hemolysis (174 mumol/L hemoglobin) reduces osteocalcin concentration by 54%. High concentrations of triglycerides (7 mmol/L) give an overestimation of 63%. Serum concentrations of osteocalcin measured in 130 healthy subjects (ages 15-64 years) and 86 children (ages 4-14 years) were 1.4 +/- 0.8 and 4.0 +/- 1.5 nmol/L (8.1 +/- 4.6 and 22.5 +/- 8.6 micrograms/L), respectively (mean +/- SD).
Jaouhari
J
J
Laboratoire du Centre de Médecine Préventive, Vandoeuvre-les-Nancy, France.
Schiele
F
F
Dragacci
S
S
Tarallo
P
P
Siest
J P
JP
Henny
J
J
Siest
G
G
D000293:Adolescent; D000328:Adult; D000437:Alcoholism / Q000097:blood; D000925:Anticoagulants; D001360:Avidin; D001667:Binding, Competitive; D001710:Biotin; D002122:Calcium Chloride / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006111:Graves Disease / Q000097:blood; D006461:Hemolysis; D006801:Humans; D007124:Immunoenzyme Techniques / Q000592:standards / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood*; D011786:Quality Control; D011863:Radioimmunoassay; D012016:Reference Values; D014280:Triglycerides / Q000097:blood
D000925:Anticoagulants; D014280:Triglycerides; D015675:Osteocalcin; D001360:Avidin; D001710:Biotin; D002122:Calcium Chloride