Chienwichai Kittiphan, Jiwakanon Sirin, Chaiviriyawong Kamonrat, Wattanakul Jananya, Rojnsaengroung Warat, Manasuth Soravit, Sangkaew Sorawat, Chang Arunchai, Mongkolrattanakul Pannawat
Division of Nephrology, Department of Internal Medicine, Hatyai Hospital, 182 Ratthakan, Tambon Hat Yai, Hat Yai District, Songkhla, 90110, Thailand.
Department of Internal Medicine, Hatyai Hospital, Songkhla, Thailand.
Sci Rep. 2025 Aug 7;15(1):28883. doi: 10.1038/s41598-025-14881-5.
Accurately distinguishing hypovolemic hyponatremia from the syndrome of inappropriate antidiuresis (SIAD) remains challenging due to limitations in traditional pre-saline infusion urine sodium measurements. This prospective cohort study at two Thai medical centers evaluated whether post-saline infusion urine sodium improves diagnostic accuracy. We enrolled 113 hospitalized adults with non-edematous hypotonic hyponatremia (serum sodium < 130 mmol/L). Asymptomatic patients received 500 mL of 0.9% saline, while symptomatic patients received 150 mL of 3% saline. Urine sodium was measured before and after infusion (Time 1). Diagnostic performance was assessed using AUC curves, with Youden's J statistic determining optimal cutoffs. Post-infusion urine sodium at Time 1 demonstrated superior accuracy compared to pre-infusion measurements (AUC 0.75 vs. 0.61, P = 0.01). A cutoff of 24.5 mmol/L at Time 1 achieved 75.2% accuracy (95% CI: 66.2-82.9), 62.5% sensitivity (95% CI: 45.8-77.3), and 82.2% specificity (95% CI: 71.5-90.2). These findings highlight the clinical utility of post-saline urine sodium. In conclusion, measuring urine sodium after saline infusion significantly improves differentiation between hypovolemic hyponatremia and SIAD compared to pre-infusion testing. The 24.5 mmol/L cutoff at Time 1 offers a practical, evidence-based threshold for clinicians, reducing misdiagnosis risks and guiding appropriate fluid management in hyponatremic patients.
由于传统的输注生理盐水前尿钠测量存在局限性，准确区分低血容量性低钠血症和抗利尿激素分泌失调综合征（SIAD）仍然具有挑战性。这项在泰国两个医学中心开展的前瞻性队列研究评估了输注生理盐水后尿钠是否能提高诊断准确性。我们纳入了113例住院的非水肿性低渗性低钠血症成人患者（血清钠<130 mmol/L）。无症状患者输注500 mL 0.9%生理盐水，有症状患者输注150 mL 3%生理盐水。在输注前后（时间1）测量尿钠。使用AUC曲线评估诊断性能，通过约登指数确定最佳临界值。时间1的输注后尿钠显示出比输注前测量更高的准确性（AUC 0.75对0.61，P = 0.01）。时间1时24.5 mmol/L的临界值准确率达到75.2%（95% CI：66.2 - 82.9）[此处疑似多了个逗号，原文可能是95%CI:66.2-82.9]，敏感性为62.5%（95% CI：45.8 - 77.3），特异性为82.2%（95% CI：71.5 - 90.2）。这些发现突出了输注生理盐水后尿钠的临床实用性。总之，与输注前检测相比，输注生理盐水后测量尿钠显著提高了低血容量性低钠血症和SIAD之间的鉴别能力。时间1时24.� mmol/L的临界值为临床医生提供了一个实用的、基于证据的阈值，降低了误诊风险，并指导低钠血症患者进行适当的液体管理。
