Comparison of Architect i2000sr and Cobas e601 Systems for Determining Serum Human Chorionic Gonadotropin-Beta.
BACKGROUND
Human chorionic gonadotropin-beta (β-hCG) is an important index used to monitor embryonic development following embryo transfer. Architect i2000sr and Cobas e601 are widely used automated immunoassay systems used to measure serum β-hCG concentrations; however, the correlations between serum β-hCG levels measured with these two immunoassays and the accuracy of the immunoassays have not been fully evaluated.


METHODS
Serum β-hCG levels were measured in 133 serum samples using the Architect i2000sr and Cobas e601 automated immunoassay systems. Passing-Bablok regression analysis was used to compare the correlation in serum β-hCG levels obtained using the two immunoassays. A Bland-Altman plot analysis was used to identify mean ratios and 95% CIs of the mean ratios of the β-hCG results between the two immunoassays. In this graphical method the mean ratios between the two techniques were plotted against the averages of the two techniques.


RESULTS
The total coefficients of variations (CVs) of serum β-hCG ranged from 3.12 - 4.66% for Cobas e601 and 3.18 - 4.99% for Architect i2000sr. The measured value of serum β-hCG detected by the two immunoassays was statistically significant (p < 0.001). The Passing-Bablok regression analysis showed good correlation between the serum β-hCG values measured using the two systems. At a low concentration of serum β-hCG (< 10000 IU/L, n = 52), the correlation coefficient r was 0.9628. At a high concentration of serum β-hCG (> 10000 IU/L, n = 81), the correlation coefficient r was 0.8076. The Bland-Altman plot analysis showed that the measured value of serum β-hCG detected by Architect i2000sr was about 1.25 times higher than that of Cobas e601. The mean ratio was 1.12 at a low concentration of serum β-hCG, and it was 1.33 at a high concentration.


CONCLUSIONS
Architect i2000sr and Cobas e601 have good concordance for determining serum β-hCG. However, the β-hCG values measured with Architect i2000sr were 25% higher than those obtained using Cobas e601.
Xiaoyong
X
Guan
Yifan
Y
Sun
Hongyu
H
Zhang
Ka
K
Liang
Kang
K
Long
Jin
J
Li
Shifu
S
Tang
Chunming
C
Liu
D000328:Adult; D015415:Biomarkers / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D004624:Embryo Transfer; D047108:Embryonic Development; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D011247:Pregnancy; D012044:Regression Analysis
D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human