血常规指标对儿童铁缺乏的预测作用

目的探讨血常规指标在筛查儿童铁缺乏中的预测价值。方法回顾性分析2017年6月至2019年5月浙江大学医学院附属儿童医院1443名6月龄~18岁健康体检儿童(男862名、女581名)的血常规指标及血清铁蛋白(SF)水平。以SF<20μg/L为铁缺乏判断依据,同时伴有贫血(6月龄~5岁血红蛋白<110 g/L,6~18岁血红蛋白<120 g/L)为缺铁性贫血(IDA)组:SF<20μg/L同时排除贫血为无贫血铁缺乏组,SF≥20μg/L合并贫血者为铁状态不明贫血组,SF≥20μg/L无贫血者为健康对照组。定量资料以±s或M(四分位间距)描述,组间比较应用方差分析或非参数秩和检验分析,并应用受试者工作特征曲线(ROC)分析血常规指标及低血红蛋白密度百分比(LHD)对IDA及铁缺乏的预测价值。结果1443名儿童年龄2.1(3.3)岁,健康对照组1061例,无贫血铁缺乏组292例,铁状态不明贫血组43例,IDA组47例。铁缺乏发生率高于贫血发生率[23.5%(339/1443)比6.2%(90/1443),χ2=169.76,P<0.01]。无贫血铁缺乏组LHD、红细胞分布宽度(RDW)均高于健康对照组[0.088(0.093)比0.073(0.068),0.131±0.013比0.126±0.008,P均<0.01],平均红细胞体积(MCV)、平均血红蛋白浓度(MCHC)均低于健康对照组[(80±4)比(83±4)fl,(326±9)比(329±8)g/L,P均<0.01];IDA组LHD[0.322(0.544)]、RDW(0.151±0.018)均高于无贫血铁缺乏组,MCV[(73±6)fl]、MCHC[(309±14)g/L]均低于无贫血铁缺乏组(P均<0.01)。MCHC、LHD、RDW、MCV预测铁缺乏的曲线下面积(AUC)分别为0.63(95%CI:0.60~0.67)、0.63(95%CI:0.60~0.67)、0.67(95%CI:0.63~0.70)和0.73(95%CI:0.69~0.76)。以MCV<80.2 fl、RDW>0.131或MCHC<322 g/L为界值,筛查铁缺乏的灵敏度分别为0.540、0.469和0.336,均高于血红蛋白筛查铁缺乏的灵敏度(0.139,χ2=121.70、87.47、35.56,P均<0.01)。结论血常规中MCV、RDW、MCHC均可作为铁缺乏的筛查指标,简便易于基层推广。

Predictive values of routine blood test results for iron deficiency in children

Objective To explore the predictive values of routine blood test results for iron deficiency(ID)screening in children.Methods Routine blood test results and serum ferritin(SF)levels from 1443 healthy children(862 boys,581 girls)aged 6 months to 18 years,who were seen for well-child visits between June 2017 and May 2019 in Children′s Hospital,Zhejiang University School of Medicine,were retrospectively analyzed.ID was defined as SF<20μg/L,iron deficiency anemia(IDA)as ID with anemia(hemoglobin(Hb)<110 g/L at 6 months-5 years of age,Hb<120 g/L at 6-18 years of age),non-anemia ID as ID without anemia,non-ID anemia as SF≥20μg/L with anemia,and healthy control subjects as those with SF≥20μg/L but without anemia.The blood test results including Hb,mean corpuscular volume(MCV),mean corpuscular hemoglobin concentration(MCHC),red blood cell distribution width(RDW),and the percentage of low hemoglobin density(LHD)of healthy control,non-anemia ID,non-ID anemia,and IDA groups were compared by analysis of variance(ANOVA)or non-parametric test,quantitative data were described as±s or M(interquartile range),and receiver operating characteristic curve(ROC)analysis was applied to assess predictive values of routine blood test results and LHD for detecting IDA and ID.Results Among 1443 children with median age of 2.1(3.3)years,1061 children were in healthy control group,292 in non-anemia ID group,43 in non-ID anemia group and 47 in IDA group.The prevalence of ID was much higher than that of anemia(23.5%(339/1443)vs.6.2%(90/1443),χ2=169.76,P<0.01).Compared with control group,non-anemia ID group showed higher LHD(0.088(0.093)vs.0.073(0.068),P<0.01)and RDW(0.131±0.013 vs.0.126±0.008,P<0.01),lower MCV((80±4)vs.(83±4)fl,P<0.01)and MCHC values((326±9)vs.(329±8)g/L,P<0.01).IDA group showed higher LHD(0.322(0.544))and RDW(0.151±0.018),lower MCV((73±6)fl)and MCHC values((309±14)g/L)than non-anemia ID group(all P<0.01).The area under curve(AUC)values of MCHC,LHD,RDW and MCV for detecting ID were 0.63(95%CI:0.60-0.67),0.63(95%CI:0.60-0.67),0.67(95%CI:0.63-0.70)and 0.73(95%CI:0.69-0.76)respectively.With cutoff limits(MCV<80.2 fl,RDW>0.131 or MCHC<322 g/L),MCV,RDW and MCHC showed higher sensitivity for screening ID than hemoglobin(0.540,0.469 and 0.336 vs.0.139,χ2=121.70,87.47,35.56,all P<0.01).Conclusion MCV,RDW and MCHC can be used to screen ID in primary health care settings.