Hill Peter G, Forsyth Julia M, Rai Baldeep, Mayne Stewart
Department of Chemical Pathology, Derbyshire Royal Infirmary, Derby Hospitals National Health Service Foundation Trust, Derby, United Kingdom.
Clin Chem. 2006 Sep;52(9):1743-8. doi: 10.1373/clinchem.2006.069104. Epub 2006 Jul 20.
Retrospective analyses have established the role of quantitative serum free light chains (FLCs) in the diagnosis of monoclonal light chain disorders. The aims of this study were to assess (a) whether the addition of serum FLCs to serum protein electrophoresis (SPEP) identified additional patients with monoclonal gammopathies; (b) whether serum FLC measurements could replace urinalysis for Bence Jones protein (BJP); and (c) the cost/quality implications of routinely measuring serum FLCs.
Serum FLCs were added to consecutive requests for SPEP from August to November 2004 and measured by automated immunoassay.
Seventy-one of 923 patients had abnormal serum FLC ratios. Seven patients with monoclonal gammopathies and 1 patient with malignant lymphoma (but no monoclonal band) were detected among 43 patients with negative SPEP but positive serum FLC ratios. Thirty-five patients with negative SPEP had false-positive serum FLC ratios. The false-positive rate for a ratio >1.65 was higher than previously described and associated with polyclonal increases in immunoglobulins and renal impairment. Serum FLC ratios were normal in 2 of 13 patients with low-level persistent urine BJP. However, no significant pathology would have been missed by replacing BJP with serum FLCs. Revenue and manpower savings offset 60% of the costs of serum FLCs.
Additional diagnostic information is gained by adding serum FLCs to SPEP as first-line tests for investigating possible B-cell disorders. The quality of the diagnostic service is enhanced by more confident exclusion of light chain disorders and improved interpretive assessment of SPEP and immunofixation electrophoresis.
回顾性分析已确立了定量血清游离轻链（FLC）在单克隆轻链病诊断中的作用。本研究的目的是评估：（a）在血清蛋白电泳（SPEP）基础上增加血清FLC检测是否能识别出更多单克隆丙种球蛋白病患者；（b）血清FLC检测是否可替代尿本-周蛋白（BJP）检测；（c）常规检测血清FLC的成本/质量影响。
2004年8月至11月，在连续要求进行SPEP检测的样本中增加血清FLC检测，并采用自动化免疫测定法进行测量。
923例患者中有71例血清FLC比例异常。在43例SPEP阴性但血清FLC比例阳性的患者中，检测到7例单克隆丙种球蛋白病患者和1例恶性淋巴瘤患者（但无单克隆条带）。35例SPEP阴性患者的血清FLC比例为假阳性。比例>1.65时的假阳性率高于先前报道，且与免疫球蛋白的多克隆增加和肾功能损害有关。13例持续性低水平尿BJP患者中有2例血清FLC比例正常。然而，用血清FLC替代BJP检测不会漏诊重大病变。收入和人力节省抵消了血清FLC检测成本的60%。
将血清FLC检测添加到SPEP中作为调查可能的B细胞疾病的一线检测可获得更多诊断信息。通过更有把握地排除轻链疾病以及改进SPEP和免疫固定电泳的解释性评估，可提高诊断服务质量。
