血糖自己測定用ランセットによる自己採取血を利用した血中コルチゾール測定法の確立とその臨床応用

Abstract

Adrenal insufficiency is caused by either primary adrenal failure or by hypothalamic-pituitary impairment. Glucocorticoid replacement therapy in patients with adrenal insufficiency is lifesaving. However, the patients usualy need to visit or be admitted to hospital for monitoring of the temporal pattern of the cortisol level, which is required for the diagnosis and evaluation of the optimal glucocorticoid replacement. To reduce the burden on the patient and to assess the pattern of cortisol level in the patient's daily life, we subjected self-collected blood to the cortisol measurement using a DetectX® Cortisol Enzyme Immunoassay Kit. The new measurement was evaluated by comparison with an established in vitro diagnostic Cortisol Ⅱ that has been introduced in hospitals. Bland-Altman analysis was used for assessing the degree of agreement between two measurements by studying the mean difference and configuring limits of agreement. The bias (mean difference) was 20.01%. This bias was significant, because the line of equality (0%) was not in the confidence interval of the bias. The 95% limits of agreement were from - 55.71 to 95.74%. Although the cortisol values obtained with Cortisol Ⅱ were 1.450μg/dL higher on average than those obtained with DetectX, the measurements of DetectX correlated with those obtained with Cortisol Ⅱ. Therefore, we conducted cortisol measurement using blood self-collected by patients at home. Plasma cortisol levels in a patient with hypopituitarism responded to administration of hydrocortisone in a dose-dependent manner A patient who had been diagnosed with depressive disorder did not show the natural cortisol circadian rhythm. Low levels of cortisol during the morning seemed to be a cause of the reduced arousal level. We concluded that the measurement of cortisol using self-colected blood was useful for determining optimal glucocorticoid replacement therapy and screening for adrenal insufficiency.