Table of Contents

HK J Paediatr (New Series)
Vol 20. No. 2, 2015

HK J Paediatr (New Series) 2015;20:115-117

Case Report

"Normal" Mean Corpuscular Volume Does Not Exclude the Diagnosis of Thalassaemia
平均紅細胞體積數值正常不能排除地中海貧血診斷

ACW Lee


Abstract

The mean corpuscular volume (MCV) measured by automated blood cell counter is a convenient way of recognising microcytosis which is a hallmark feature in the diagnosis of thalassaemic syndromes. Two children with severe thalassaemia syndrome but normal MCV measurements are described. A 17-month-old girl with homozygous b-thalassaemia and a 3-year-old girl with haemoglobin H-Constant Spring disease presented with anaemia. Results from the automated blood cell counter showed haemoglobin of 7.0 g/dL and 8.0 g/dL (normal, 11.0-15.0), respectively, with corresponding MCV of 80.5 fL and 79.3 fL (normal, 70.0-90.0), respectively. Microcytosis and hypochromia, however, were prominent on microscopic examination of the peripheral blood smear, which led to the correct diagnosis. Paediatricians and family physicians should be alerted to the potential pitfalls when interpreting the results provided by automated blood cell counters. Microscopic examination of the peripheral blood smear is indispensable in the evaluation of anaemic children.

通過血細胞自動計數儀檢測平均紅細胞體積(MCV)是發現小細胞較為簡便的辦法,而小細胞則是地中海貧血綜合徵診斷的一個典型特徵。本文報導了兩例MCV數值正常的嚴重地中海貧血綜合徵患兒。一名17個月大女童患有純合子性β地中海貧血,另一名3歲大女童患有Constant-Spring型血紅蛋白H病,表現為貧血。血細胞自動計數儀顯示血紅蛋白分別為7 g/dL和8 g/dL(正常為11.0-15.0),相應MCV分別為80.5 fL 和 79.3 fL(正常為 70.0-90.0)。但是顯微鏡檢外週血塗片可以發現明顯的小細胞和低色素,從而得到正確診斷。兒科醫生和家庭醫生在解讀血細胞自動計數儀檢測結果時,應該留意結果潛在的錯漏。顯微鏡檢貧血患兒的外週血塗片是不可或缺的檢查。

Keyword : Anaemia, hypochromic microcytic; Erythrocyte indices; Haemoglobin H disease; Mean corpuscular volume; Thalassaemia, beta

關鍵詞:貧血,小細胞低色素、紅細胞指數、血病蛋白H病、平均紅細胞體積、地中海貧血,β

 
 

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