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Improved protein-binding radioassay for plasma cortisol
Clinical Chemistry
|February 1, 1980
Summary
This study presents a faster method for measuring plasma cortisol using filter paper and dichloromethane extraction. The improved radioassay allows for rapid, accurate analysis of numerous samples for clinical research.
Area of Science:
- Clinical Chemistry
- Endocrinology
- Analytical Chemistry
Background:
- Accurate measurement of plasma cortisol is crucial for diagnosing adrenal disorders.
- Existing methods for cortisol analysis can be time-consuming and labor-intensive.
- There is a need for rapid, high-throughput assays for total plasma cortisol.
Purpose of the Study:
- To describe an improved competitive protein-binding radioassay for total plasma cortisol.
- To enable rapid analysis of a large number of plasma samples.
- To validate the accuracy and reliability of the new method.
Main Methods:
- Utilized a Whatman 3MM filter-paper strip for direct plasma application (0.1 mL).
- Employed a single dichloromethane extraction of the filter paper.
- Assayed the extracted residue directly using a micro-method based on Murphy's technique.
Main Results:
- Achieved excellent agreement with the original Murphy method (ethanol extraction), with a correlation coefficient (r) of 0.988.
- Demonstrated the capability to easily assay one hundred samples in duplicate simultaneously.
- The modified method allows for significantly faster sample processing.
Conclusions:
- The improved radioassay provides a rapid and efficient method for total plasma cortisol determination.
- This technique is suitable for high-volume sample analysis in clinical and research settings.
- The method maintains high accuracy comparable to established protocols.
