In the realm of endocrine diagnostics, Professor Brian Keevil is a beacon of innovation, guiding the way towards more accurate and patient-friendly testing methods. As the Clinical Lead for Biochemistry at Manchester University NHS Foundation Trust, Keevil's expertise lies in the development and implementation of advanced mass spectrometry techniques, particularly in endocrinology. His work has revolutionized the way we approach adrenal disorders, such as Cushing's syndrome and adrenal insufficiency, by harnessing the power of salivary cortisone testing.
A New Approach to Adrenal Disorders
Keevil's interest in salivary cortisol and cortisone stems from a desire to simplify and improve the diagnostic process. Traditional blood-based testing, while effective, can be inconvenient and burdensome for patients. Saliva, on the other hand, is easily accessible and can be collected at home, making it a more patient-friendly option. This shift towards non-invasive testing is particularly significant in the context of endocrine disorders, where early intervention is crucial.
The Advantages of Salivary Cortisone
One of the key advantages of salivary cortisone is its sensitivity and correlation with serum cortisol levels. Unlike free cortisol, which represents only around 5% of circulating cortisol, salivary cortisone offers a more linear relationship with serum cortisol concentrations. This makes it a more reliable biomarker, reflecting physiological cortisol exposure across a wider concentration range. Keevil explains, 'What we are really interested in clinically is free cortisol, which represents only around 5% of circulating cortisol because the majority is bound to proteins. When free cortisol enters the salivary gland, much of it is converted into cortisone by the enzyme 11β-hydroxysteroid dehydrogenase type 2.'
Diagnosing Adrenal Insufficiency
Adrenal insufficiency, a potentially life-threatening condition, is often underdiagnosed due to nonspecific symptoms and resource-intensive screening tests. Keevil's research has shown that waking salivary cortisone collected at home can act as an effective first-line screening test. This non-invasive approach reduces the need for hospital visits and specialist staff, making it more accessible and practical for patients. Several UK hospitals are now implementing or evaluating this approach, and Manchester University NHS Foundation Trust has already begun routine use of the test.
Cushing's Syndrome: A Complex Diagnosis
Cushing's syndrome, another challenging endocrine disorder, lacks a single definitive test. Keevil's studies have demonstrated the effectiveness of late-night salivary cortisone in diagnosing pituitary-dependent Cushing's disease. With a sensitivity of 95% and specificity of 100%, it outperformed other tests, making it a valuable tool for identifying this complex condition.
Salivary Cortisone and Dexamethasone Suppression Testing
Keevil's research has also explored the use of salivary cortisone alongside the overnight dexamethasone suppression test. This combination provides excellent diagnostic performance, with sensitivity around 85% and specificity around 92% for detecting cortisol excess. By removing the need for patients to attend the hospital the morning after taking dexamethasone, the process becomes significantly more convenient.
The Future of Salivary Cortisone Testing
Looking ahead, Keevil envisions salivary cortisone becoming an increasingly important part of clinical practice. He believes it will continue to gain traction as a routine outpatient and home-based test, offering excellent diagnostic performance and convenience for patients. As more centers adopt LC-MS/MS methodologies, the potential for saliva-based steroid testing to revolutionize endocrine medicine is immense.
In conclusion, Professor Brian Keevil's work on salivary cortisone testing represents a significant step forward in endocrine diagnostics. By harnessing the power of non-invasive testing, he is improving the accuracy and accessibility of adrenal disorder diagnosis, ultimately enhancing patient care and outcomes.
