Is chemiluminescent immunoassay an appropriate substitution for radioimmunoassay in monitoring estradiol levels?
OBJECTIVE
To determine the correlation between serum estradiol measurements by chemiluminescent immunoassay (CIA) vs. radioimmunoassay (RIA) in two groups: patients treated with gonadotropins and patients treated with oral estrogen.


METHODS
Prospective study.


METHODS
Assisted Reproductive Technology (ART) program based in a university-affiliated hospital in Manhasset, New York.


METHODS
Three hundred forty-eight patients undergoing gonadotropin stimulation and 63 patients receiving oral estrogen between July and December, 1997.


METHODS
Estradiol levels were measured concomitantly on all patients undergoing gonadotropin stimulation for IVF and all patients receiving oral estrogen for a frozen-thaw cycle.


METHODS
RIA:CIA ratio.


RESULTS
In the group undergoing gonadotropin stimulation, the median RIA:CIA ratio was 0.92, RIA = 1.26 x CIA(0.96), r = 0.98. In the group receiving oral estrogen, the median ratio was 3.93, RIA = 2.9 x CIA(1.05), r = 0.89.


CONCLUSIONS
Estradiol levels determined by CIA correlate closely with RIA results for patients being treated with gonadotropins. Conversely, for patients receiving oral estrogen, CIA levels are one-third or less of the RIA level.
Hershlag
A
A
North Shore University Hospital, New York University School of Medicine, Manhasset, New York, USA.
Zinger
M
M
Lesser
M
M
Scholl
G
G
Bjornson
L
L
D000284:Administration, Oral; D015925:Cryopreservation; D004958:Estradiol / Q000097:blood* / Q000627:therapeutic use; D005260:Female; D005307:Fertilization in Vitro; D006062:Gonadotropins / Q000627:therapeutic use; D006801:Humans; D007118:Immunoassay; D008163:Luminescent Measurements; D011446:Prospective Studies; D011863:Radioimmunoassay
D006062:Gonadotropins; D004958:Estradiol