Evaluation of Fluorescence Excitation Transfer Immunoassay for Plasma Cortisol Measurement
Author Information
Author(s): J. Calvin, K. Burling, R. S. Campbell, S. A. P. Chubb, C. P. Price
Primary Institution: Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge
Hypothesis
The fluorescence excitation transfer immunoassay can accurately measure plasma cortisol levels.
Conclusion
The cortisol assay is simple to perform and shows good precision compared to existing methods.
Supporting Evidence
- The assay showed a recovery range of 99 to 114% when spiked with cortisol.
- The precision of the assay was comparable to that of the radioimmunoassay currently in use.
- The calibration curve remained stable over a 24-hour period.
- Hyperbilirubinaemia and lipaemia did not affect the assay results.
- Haemolysed specimens produced falsely high results due to interference from haemoglobin.
Takeaway
This study tested a new way to measure cortisol in blood, and it worked well and was easy to use.
Methodology
The study used fluorescence excitation transfer immunoassay to measure cortisol in plasma samples, comparing results with radioimmunoassay and HPLC methods.
Potential Biases
Potential interference from substances like prednisolone was noted, which could lead to inaccurate results.
Limitations
The study did not screen samples for the presence of interferents, which may affect results.
Participant Demographics
Plasma pools were prepared from patients' samples, but specific demographics were not detailed.
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