2017 Volume 66 Issue 2 Pages 133-140
Parathyroid hormones (PTHs) are analyzed by intact-PTH or whole-PTH assay. The intact-PTH assay detects PTH (1–84) and PTH (7–84), whereas the whole-PTH assay detects only PTH (1–84). The whole-PTH assay could be performed using only the immunoradiometric assay (IRMA) method, but now, it can also be performed using CLEIA and ECLIA with an automatic analyzer. Therefore, we performed a basic study of CLEIA and ECLIA and compared the two methods. Both methods have good repeatability and intermediate precision. However, there was a high tendency of ECLIA to show dilutional linearity in the low concentration range. No effect of interfering substances was observed up to a final concentration of each substances. The preservation stabilities for both methods are poorer in serum than in EDTA-2Na plasma, and PTH value was most unstable at room temperature. The IRMA method has a lower PTH value than CLEIA or ECLIA. Changes in the trend of the concentration band are seen in the comparison between CLEIA and ECLIA. A good correlation was obtained in the comparison between serum and EDTA-2Na plasma in CLEIA and ECLIA. Higher concentrations of PTHs determined using MPC-treated containers than using untreated containers were confirmed. Since the adsorption reaction to the container is known to be suppressed by applying the MPC process, this phenomenon was considered to be due to the adsorption of PTH to the storage container. The IRMA method, which is a conventional method with relatively high stability, was shown in the present study to be useful in combination with CLEIA.
