Is supine rest necessary before blood sampling for plasma metanephrines?
Is supine rest necessary before blood sampling for plasma metanephrines?
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DOI：
10.1373/clinchem.2006.076489
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发表时间：
2007-02-01
影响因子：
9.3
通讯作者：
Sweep, C. G. J. (Fred)
中科院分区：
文献类型：
--
作者：
Lenders, Jacques W. M.;Willemsen, Jacques J.;Sweep, C. G. J. (Fred)
背景资料：在坐位与仰卧位的血液采样对血浆metanephrines诊断的影响是未知的pheochromocytoma.Methods：我们比较了血浆中游离metanephrines的浓度，从原发性高血压患者仰卧休息后获得的那些在坐位没有事先休息。我们还评估了对诊断测试性能的影响，回顾性的患者和没有嗜铬细胞瘤，我们计算的成本效益嗜铬细胞瘤testing.Results：血浆游离metanephrines的参考上限是较高的样品从坐着的病人没有事先休息，比从仰卧的病人，事先休息。将这些较高的参考上限应用于仰卧位嗜铬细胞瘤患者的样本，使诊断灵敏度从99%降至96%。在没有嗜铬细胞瘤的患者中，根据坐姿的影响调整血浆浓度，同时通过使用仰卧位参考上限保持99%的灵敏度，将假阳性检测结果的数量从9%增加到25%。结论：为了保持高诊断灵敏度，我们建议使用从仰卧位采集的血液样本中确定的参考上限。在这些条件下，患者坐位时采集的血样的阴性检测结果与仰卧休息后采集的血样的阴性结果一样有效地排除了嗜铬细胞瘤。重复测试与样品中获得的仰卧位提供了一个具有成本效益的方法来处理增加的假阳性结果后，预期在坐姿初步采样。(c)2007年美国临床化学协会
Background: The impact of blood sampling in sitting vs supine positions on measurements of plasma metanephrines for diagnosis of pheochromocytoma is unknown.Methods: We compared plasma concentrations of free metanephrines in samples from patients with primary hypertension obtained after supine rest with those obtained in the sitting position without preceding rest. We also assessed the effects on diagnostic test performance retrospectively in patients with and without pheochromocytoma, and we calculated cost-effectiveness for pheochromocytoma testing.Results: Upper reference limits of plasma free metanephrines were higher in samples obtained from seated patients without preceding rest than from supine patients with preceding rest. Application of these higher upper reference limits to samples from supine patients with pheochromocytoma decreased the diagnostic sensitivity from 99% to 96%. In patients without pheochromocytoma, adjusting the plasma concentration for the effects of sitting while preserving the 99% sensitivity by use of the supine upper reference limits increased the number of false-positive test results from 9% to 25%.Conclusions: To preserve high diagnostic sensitivity we recommend the use of upper reference limits determined from blood samples collected in the supine position. Under these conditions, negative test results for blood samples obtained with patients sitting are as effective for ruling out pheochromocytoma as negative results from samples obtained after supine rest. Repeat testing with samples obtained in the supine position offers a cost-effective approach for dealing with the increased numbers of false-positive results expected after initial sampling in the sitting position. (c) 2007 American Association for Clinical Chemistry