Browsing by Author "Ascott-Evans, Brynne"

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    An interesting D-lemma : what is all the excitement about vitamin D?
    (Medpharm Publications, 2012) Conradie, Marli; Ascott-Evans, Brynne
    There has been a dramatic interest in the importance of vitamin D, “the sunshine vitamin”, in the past few years with regard to its impact on various aspects of health and disease. Research into well-known skeletal effects, as well as extra-skeletal effects, has been overwhelming. At times it has been difficult to make informed clinical decisions regarding replacement, if needed at all. This article aims to provide the family practitioner with a summary of the most important clinical effects of vitamin D, as well as give guidelines on testing for possible deficiency and consideration of replacement thereof.
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    The role of point-of-care blood testing for ketones in the diagnosis of diabetic ketoacidosis
    (Health and Medical Publishing Group, 2015) Coetzee, Ankia; Hoffmann, Mariza; Ascott-Evans, Brynne
    Background. Urine dipstick testing for ketones is widely used when diabetic ketoacidosis (DKA) is suspected in patients with hyperglycaemia. If urinary ketones are positive, patients are referred for further management – often inappropriately, as the test is a poor surrogate for plasma ketones. Plasma beta-hydroxybutyrate (β-OHB) levels >3 mmol/L are diagnostic of DKA, while levels <1 mmol/L are insignificant. Objectives. To evaluate a hand-held electrochemical (point-of-care testing; POCT) ketone monitor and compare it with the gold-standard manual enzymatic method (MEM) for detection of plasma ketones. Methods. In a prospective and comparative study, we evaluated the measurement of β-OHB by means of POCT and the MEM in 61 consecutive samples from patients with suspected DKA at Tygerberg and Karl Bremer hospitals, Cape Town, South Africa. Capillary (for POCT) and plasma samples (for the MEM) were obtained simultaneously and compared for accuracy. Precision was assessed with control samples. Results. The POCT method was precise (coefficient of variation <4.5%), and there was a good correlation between the two methods (r=0.95). Regression analysis showed a proportional bias, with POCT reading higher than the MEM. However, when assessed at the relevant medical decision limits (β-OHB >3 mmol/L and <1 mmol/L), the total allowable error (bias + imprecision) was not exceeded. Patients will therefore still be classified correctly. The POCT method had a sensitivity of 100% and specificity of 89% for DKA (β-OHB >3 mmol/L), while at levels <1 mmol/L sensitivity was 100% and specificity 87.5%. Conclusion. The POCT device provides an accurate and precise result and can be used as an alternative to the MEM in the diagnosis of DKA.