Kavanagh Lucille, McKenna T Joseph, Fahie-Wilson Michael N, Gibney James, Smith Thomas P
Department of Investigative Endocrinology, St. Vincent's University Hospital, Dublin, Ireland.
Clin Chem. 2006 Jul;52(7):1366-72. doi: 10.1373/clinchem.2005.065854. Epub 2006 May 4.
Increased serum concentrations of macroprolactin are a relatively common cause of misdiagnosis and mismanagement of hyperprolactinemic patients.
We studied sera from a cohort of 42 patients whose biochemical hyperprolactinemia was explained entirely by macroprolactin. Using 5 pretreatments, polyethylene glycol (PEG), protein A (PA), protein G (PG), anti-human IgG (anti-hIgG), and ultrafiltration (UF), to deplete macroprolactin from sera before immunoassay, we compared residual prolactin concentrations with monomer concentrations obtained by gel-filtration chromatography (GFC). A monomeric prolactin standard was used to assess recovery and specificity of the pretreatment procedures.
Residual prolactin concentrations in all pretreated sera differed significantly (P < 0.001) from monomeric concentrations obtained after GFC. PEG underestimated (mean, 75%), whereas PA, PG, anti-hIgG, and UF overestimated (means, 178%, 151%, 178%, and 112%, respectively) the amount of monomer present. Of the 5 methods examined, PEG correlated best with GFC (r = 0.80) followed by PG (r = 0.78), PA (r = 0.72), anti-hIgG (r = 0.70), and UF (r = 0.61). After UF or pretreatment with anti-hIgG or PEG, recovery of monomeric prolactin standard was low: 60%, 85%, and 77% respectively. In contrast, pretreatment with PA or PG gave almost quantitative recovery.
None of the methods examined yielded results identical to the GFC method. PEG pretreatment yielded results that correlated best and is recommended as the first-choice alternative to GFC.
血清大泌乳素浓度升高是高泌乳素血症患者误诊和治疗不当的一个相对常见原因。
我们研究了42例患者的血清，这些患者的生化性高泌乳素血症完全由大泌乳素引起。在免疫测定前，使用5种预处理方法，即聚乙二醇（PEG）、蛋白A（PA）、蛋白G（PG）、抗人IgG（抗hIgG）和超滤（UF）从血清中去除大泌乳素，我们将残留泌乳素浓度与通过凝胶过滤色谱法（GFC）获得的单体浓度进行比较。使用单体泌乳素标准品评估预处理程序的回收率和特异性。
所有预处理血清中的残留泌乳素浓度与GFC后获得的单体浓度有显著差异（P<0.001）。PEG低估了（平均75%），而PA、PG、抗hIgG和UF高估了（平均分别为178%、151%、178%和112%）存在的单体量。在所检查的5种方法中，PEG与GFC的相关性最好（r = 0.80），其次是PG（r = 0.78）、PA（r = 0.72）、抗hIgG（r = 0.70）和UF（r = 0.61）。在进行UF或用抗hIgG或PEG预处理后，单体泌乳素标准品的回收率较低：分别为60%、85%和77%。相比之下，用PA或PG预处理可实现几乎定量的回收。
所检查的方法均未产生与GFC方法相同的结果。PEG预处理产生的结果相关性最佳，建议作为GFC的首选替代方法。
