Annals of clinical biochemistry
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Ann. Clin. Biochem. · Sep 2007
ReviewVasopressin and disorders of water balance: the physiology and pathophysiology of vasopressin.
Disorders of water balance are a common feature of clinical practice. An understanding of the physiology and pathophysiology of the key endocrine regulator of water balance vasopressin (VP) is key to diagnosis and management of these disorders. Diabetes insipidus is the result of a lack of VP or (less commonly) resistance to the renal effects of the hormone. ⋯ A comprehensive assessment of cardiovascular status and pharmacological influences are needed in these circumstances to differentiate between primary (inappropriate) and secondary (appropriate) physiological VP production. As with diabetes insipidus, diagnostic testing can help define the aetiology of hyponatraemia and direct appropriate management. Patients with disorders of water balance benefit from a joint clinical and laboratory medicine approach to diagnosis and management.
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Ann. Clin. Biochem. · Jan 2006
ReviewNational Institute for Health and Clinical Excellence guidelines on preoperative tests: the use of routine preoperative tests for elective surgery.
Clinical Guideline CG3 from the National Institute for Health and Clinical Excellence (NICE) makes recommendations on appropriate clinical practice in preoperative testing for elective surgery. Unfortunately, there is minimal evidence on which the guidelines could be based and therefore they were constructed on the basis of professional opinion. This resulted in the construction of a decision matrix of Byzantine complexity built on foundations of sand: surgical risk is estimated using an unvalidated ad hoc risk estimation method; anaesthetic risk is estimated using the American Society of Anesthesiologists (ASA) risk method that has been demonstrated to be incapable of generating consistent risk assessments. The resultant matrix may be suitable for use as a template for future research, but is extremely complex and inadequately rigorous for routine use.
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The use of herbal products in the UK is increasing, and over-the-counter herbal supplements are perceived by the public as 'safe' and 'harmless'. Although the majority of them are safe, some herbal medicines carry risks. ⋯ Other herbs are hepato- or nephrotoxic and some interact with prescription medicines. Doctors should be made aware of the need to take a herbal as well as a drug history, and the clinical laboratory has a role in helping understanding of how herbal products may affect laboratory tests and in suggesting relevant lines of investigation in patients whose symptoms may be linked to the use of herbal products.
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The degree of exposure to carbon monoxide is most often assessed by measuring the blood carboxyhaemoglobin saturation. This measurement is relevant to investigations of acute accidental or deliberate poisoning and of chronic exposure in a domestic or work place environment. ⋯ For the investigation of low-level exposure and the detection of increased haemolysis in neonates, more sensitive methods involving the release of carbon monoxide and its measurement by gas chromatography are required. Gas chromatographic methods are also appropriate when examining post-mortem blood samples where putrefaction or heat stress has resulted in a significant change in haemoglobin composition.
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Ann. Clin. Biochem. · Sep 2001
Review Comparative StudyAre natriuretic peptides clinically useful as markers of heart failure?