Division of Clinical Biochemistry & Immunology, Department of Laboratory Medicine & Pathology, Mayo Clinic, Rochester, MN, USA.
Clin Chem. 2011 Dec;57(12):1687-92. doi: 10.1373/clinchem.2011.171314. Epub 2011 Oct 6.
We analyzed serial data in patients with clinically stable monoclonal gammopathy to determine the total variation of serum M-spikes [measured with serum protein electrophoresis (SPEP)], urine M-spikes [measured with urine protein electrophoresis (UPEP)], and monoclonal serum free light chain (FLC) concentrations measured with immunoassay.
Patients to be studied were identified by (a) no treatment during the study interval, (b) no change in diagnosis and <5 g/L change in serum M-spike over the course of observation; (c) performance of all 3 tests (SPEP, UPEP, FLC immunoassay) in at least 3 serial samples that were obtained 9 months to 5 years apart; (d) serum M-spike ≥10 g/L, urine M-spike ≥200 mg/24 h, or clonal FLC ≥100 mg/L. The total CV was calculated for each method.
Among the cohort of 158 patients, 90 had measurable serum M-spikes, 25 had urine M-spikes, and 52 had measurable serum FLC abnormalities. The CVs were calculated for serial SPEP M-spikes (8.1%), UPEP M-spikes (35.8%), and serum FLC concentrations (28.4%). Combining these CVs and the interassay analytical CVs, we calculated the biological CV for the serum M-spike (7.8%), urine M-spike (35.5%), and serum FLC concentration (27.8%).
The variations in urine M-spike and serum FLC measurements during patient monitoring are similar and are larger than those for serum M-spikes. In addition, in this group of stable patients, a measurable serum FLC concentration was available twice as often as a measurable urine M-spike.
我们分析了临床稳定的单克隆丙种球蛋白血症患者的连续数据，以确定血清 M 峰的总变异（用血清蛋白电泳[SPEP]测量）、尿液 M 峰（用尿液蛋白电泳[UPEP]测量）和用免疫分析法测量的单克隆血清游离轻链（FLC）浓度。
通过以下标准来确定待研究的患者：(a) 在研究期间无治疗，(b) 诊断无变化且在观察过程中血清 M 峰变化<5 g/L；(c) 在至少 3 个相隔 9 个月至 5 年的连续样本中进行了所有 3 项检测（SPEP、UPEP、FLC 免疫分析）；(d) 血清 M 峰≥10 g/L、尿液 M 峰≥200 mg/24 h 或克隆 FLC≥100 mg/L。为每种方法计算总变异系数（CV）。
在 158 例患者队列中，90 例有可测量的血清 M 峰，25 例有尿液 M 峰，52 例有可测量的血清 FLC 异常。计算了连续 SPEP M 峰（8.1%）、UPEP M 峰（35.8%）和血清 FLC 浓度（28.4%）的 CV。将这些 CV 与室内分析 CV 相结合，我们计算了血清 M 峰（7.8%）、尿液 M 峰（35.5%）和血清 FLC 浓度（27.8%）的生物学 CV。
在患者监测期间，尿液 M 峰和血清 FLC 测量的变化相似，且大于血清 M 峰的变化。此外，在这群稳定的患者中，可测量的血清 FLC 浓度是可测量的尿液 M 峰的两倍。
