External quality control of iodine deficiency disorders laboratory in Henan province from 1999 to 2011 / 中国地方病学杂志

ABSTRACT

Objective To analyze the examination results of external quality assessment(EQA) at all levels of iodine deficiency disorders(IDD) laboratories in Henan province and the network operation to further standardize and improve the laboratory,and to provide reliable laboratory quality assurance for surveillance and control of IDD.Methods The examination results of EQA at all levels of IDD laboratories in Henan province were statistically analyzed in accordance with the National Reference Laboratory (NRL) of IDD (1999-201 1).Results The survey results showed that the provincial level laboratory was all qualified in testing urinary iodine and salt iodine in the past 13 years.In prefectural level,the laboratory response rates were 100.0％,and through participation in EQA,laboratory capacity had been significantly increased and stabilized.From 1999 to 2001,the passing rate of check up of urinary iodine was 22.2％ (4/18),72.2％ (13/18),94.4％ (17/18),respectively,and the rate was stable at 100.0％(18/18) from 2002 to 2011 except 94.4％ (17/18) in 2003.Since 2000,the prefectural level laboratory began to take part in the salt iodine EQA,and the laboratory response rate was 100.0％ (18/18) from 2000 to 2011.Except 88.9％(16/18) in 2003,the passing rate of check up of urinary iodine was 100.0％(18/18)from 2000 to 2011.In 2003 and 2004,6 to 7 county-level laboratories participated in the EQA of urinary iodine in Zhengzhou city,respectively,and all qualified.The number of county-level laboratories that participated in the salt iodine quality control network increased from 29 in 1999 to 148 in 2011.Response rate was 94.4％(68/72),96.7％(58/60) and 92.3％(144/156)in 2003,2006 and 2007,respectively,and the rate remained stable at 100.0％ in the remaining 10 years.In 1999,the passing rate was 69.0％ (20/29),then increased significantly,except 86.7％ (26/30) in 2001 and 84.6％(132/156) in 2007,the rates were all above 90.0％ in other years,especially in 2000 and 2009,the passing rates were both 100.0％.Conclusions The accuracy of test results of external quality controls and the normal operation of the network at all levels of laboratories is closely related to the IDD laboratory conditions and detection techniques.