Abstract：
Serum free light chain (FLC) concentration is greatly affected by kidney function. Using a large prospective population-based cohort, we aimed to establish a reference interval for FLCs in persons with chronic kidney disease (CKD). A total of 75422 participants of the iStopMM study were screened with serum FLC, serum protein electrophoresis and immunofixation. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine. Central 99% reference intervals were determined, and 95% confidence intervals calculated. Included were 6461 (12%) participants with measured FLCs, eGFR < 60 mL/min/1.73 m2, not receiving renal replacement therapy, and without evidence of monoclonality. Using current reference intervals, 60% and 21% had kappa and lambda FLC values outside the normal range. The FLC ratio was outside standard reference interval (0.26-1.65) in 9% of participants and outside current kidney reference interval (0.37-3.10) in 0.7%. New reference intervals for FLC and FLC ratio were established. New reference intervals for the FLC ratio were 0.46-2.62, 0.48-3.38, and 0.54-3.30 for eGFR 45-59, 30-44, and < 30 mL/min/1.73 m2 groups, respectively. The crude prevalence of LC-MGUS in CKD patients was 0.5%. We conclude that current reference intervals for FLC and FLC ratio are inaccurate in CKD patients and propose new eGFR based reference intervals to be implemented.
摘要：
血清游离轻链(FLC)浓度受肾功能影响较大。使用一个庞大的前瞻性基于人群的队列，我们旨在建立慢性肾脏病(CKD)患者FLC的参考区间.iStopMM研究的75422名参与者接受了血清FLC筛查，血清蛋白电泳和免疫固定。根据血清肌酐计算估计的肾小球滤过率（eGFR）。确定了99%的中心参考区间，并计算95%的置信区间。包括6461名(12%)具有测量FLC的参与者，eGFR<60mL/min/1.73m2，未接受肾脏替代治疗，没有单克隆的证据.使用当前参考间隔，60%和21%具有超出正常范围的κ和λFLC值。9％的参与者的FLC比率在标准参考区间（0.26-1.65）之外，在0.7％的当前肾脏参考区间（0.37-3.10）之外。建立FLC和FLC比率的新参考间隔。对于eGFR45-59、30-44和<30mL/min/1.73m2组，FLC比率的新参考区间为0.46-2.62、0.48-3.38和0.54-3.30。分别。CKD患者中LC-MGUS的粗患病率为0.5%。我们得出的结论是，CKD患者中FLC和FLC比率的当前参考间隔不准确，并提出了新的基于eGFR的参考间隔。
