以流式細胞儀建立診斷遺傳性球型紅血球增多症之標準檢驗方法

Flow Cytometry as a Standard Procedure for the Diagnosis of Hereditary Spherocytosis

遺傳性球型紅血球增多症（HS）是一種紅血球膜結構上的遺傳性異常，傳統上以紅血球脆性試驗進行篩檢，此項試驗非常的耗時、費力，且至少須取得9 ml的全血。EMA是一種螢光染劑，會與紅血球膜蛋白band 3上的Lys-430形成共價性鍵結；HS病患band 3蛋白數量會有下降的狀況，造成EMA螢光強度下降。為增進HS病患的篩檢能力，我們標準化流式細胞儀偵測EMA的步驟，透過ROC curve取得正常人與病患的cut-off值，並且分析HS病患分別在EMA試驗與脆性試驗的結果表現。總結來說，與脆性試驗相較，EMA試驗擁有較佳的靈敏度及專一性，操作簡易，數小時內便可得到結果。EMA試驗僅需少量的全血檢體，也適合在新生兒需要篩檢時使用。

Hereditary spherocytosis (HS) is a hereditary disorder of membrane structure on red blood cells. Traditional laboratory screening for HS is osmotic fragility test, which is labor-intensive and time-consuming requiring at least 9 ml of whole blood. EMA is a fluorescence dye, which binds covalently Lys-430 on the band 3 RBC membrane protein. The decrease of band 3 protein in HS patient results in the lower EMA fluorescence intensity. To improve the HS screening, we standardize the protocol of EMA flow cytometry. Set up a cut-off value through ROC curve to discriminate the normal individuals and HS patients. We also compare the performance between the EMA flow cytometry and OF test in a series of HS patients. Compared to the OF test, the EMA test has a better sensitivity and specificity, is easier to practice, and the results are available in hours. The EMA test needs small volume of whole blood, more suitable for neonatal screening.