Baid Smita K, Sinaii Ninet, Wade Matt, Rubino Domenica, Nieman Lynnette K
Reproductive Biology and Medicine Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-1109, USA.
J Clin Endocrinol Metab. 2007 Aug;92(8):3102-7. doi: 10.1210/jc.2006-2861. Epub 2007 Jun 5.
Although bedtime salivary cortisol measurement has been proposed as the optimal screening test for the diagnosis of Cushing's syndrome, its performance using commercially available assays has not been widely evaluated.
Our objective was to compare RIA and tandem mass spectrometry (LC-MS/MS) measurement of salivary cortisol in obese subjects and healthy volunteers.
We conducted a cross-sectional prospective study of outpatients.
We studied 261 obese subjects (186 female) with at least two additional features of Cushing's syndrome and 60 healthy volunteers (30 female). Subjects provided split bedtime salivary samples for cortisol measurement by commercially available RIA and LC-MS/MS. Results were considered normal or abnormal based on the laboratory reference range. Subjects with abnormal results underwent evaluation for Cushing's syndrome.
In paired samples, RIA gave a lower specificity than LC-MS/MS in obese subjects (86 vs. 94%, P = 0.008) but not healthy volunteers (86 vs. 82%, P = 0.71). Among subjects with at least one abnormal result, both values were abnormal in 44% (confidence interval 26-62%) of obese and 75% (confidence interval 33-96%) of healthy volunteers. In obese subjects, salivary cortisol concentrations were less than 4.0 to 643 ng/dl (<0.11-17.7 nmol/liter; normal, < or =100 ng/dl, 2.80 nmol/liter) by LC-MS/MS and less than 50 to 2800 ng/dl (1.4-77.3 nmol/liter; normal, < or =170 ng/dl, 4.7 nmol/liter) by RIA. Cushing's syndrome was not diagnosed in any subject.
Salivary cortisol levels should not be used as the sole test to diagnose Cushing's syndrome if laboratory-provided reference ranges are used for diagnostic interpretation.
尽管有人提出睡前唾液皮质醇测量是库欣综合征诊断的最佳筛查试验，但使用市售检测方法的性能尚未得到广泛评估。
我们的目的是比较肥胖受试者和健康志愿者唾液皮质醇的放射免疫分析（RIA）和串联质谱法（LC-MS/MS）测量结果。
我们对门诊患者进行了一项横断面前瞻性研究。
我们研究了261名肥胖受试者（186名女性），他们至少具有库欣综合征的另外两个特征，以及60名健康志愿者（30名女性）。受试者提供睡前唾液样本，通过市售的RIA和LC-MS/MS测量皮质醇。根据实验室参考范围将结果视为正常或异常。结果异常的受试者接受库欣综合征评估。
在配对样本中，肥胖受试者中RIA的特异性低于LC-MS/MS（86%对94%，P = 0.008），但在健康志愿者中并非如此（86%对82%，P = 0.71）。在至少有一项异常结果的受试者中，肥胖受试者中有44%（置信区间26 - 62%）和健康志愿者中有75%（置信区间33 - 96%）的两项值均异常。在肥胖受试者中，通过LC-MS/MS测量的唾液皮质醇浓度低于4.0至643 ng/dl（<0.11 - 17.7 nmol/升；正常，≤100 ng/dl，2.80 nmol/升），通过RIA测量的低于50至2800 ng/dl（1.4 - 77.3 nmol/升；正常，≤170 ng/dl，4.7 nmol/升）。所有受试者均未诊断出库欣综合征。
如果使用实验室提供的参考范围进行诊断解读，唾液皮质醇水平不应作为诊断库欣综合征的唯一检测方法。
