Investigation And Clinical Analysis On The Reference Range For Serum TSH During Pregnancy Trimesters-specific Serum TSH For Chongzhou People's Hospital

Objective: to establish the reference range for Pregnancy Trimesters-specific Serum TSH for Chongzhou People's Hospital.Method: A total of 523 pregnant women of in different pregnancy were selected from all pregnant women received a series of relevant examination and set up records in the Outpatient Clinic of Obstetrics of Chongzhou People's Hospital during January,2017 and October,2017 as the “representational population”.The selection process was done through inquiry and physical examination using the method,the inclusion and exclusion criteria recommended by the National Academy of Clinical Biochemistry(NACB).Among all these selected pregnant women,217 are categorized into the first trimester(T1,less than 12 weeks and 6 days).155 are categorized into the second trimester(T2,from 13 weeks to 27 weeks and 6 days).151 are categorized into the third trimester(T3,more than 28 weeks).Acridinium ester direct chemiluminescent immunoassay was adopted to measure the serum thyroid hormone level of the “representational population” using Simens ADVIA Centaur XP immunoassay system and its reagents(Germany).The measurement results were then compiled into a database using Excel 2010 and statistically analyzed using SPSS 21.0.The reference ranges were established using medians and the 95% confidence intervals(between 2.5 and 97.5 percentiles).The established reference ranges were then used to analyze the change patterns of pregnancy trimesters-specific serum TSH during the three pregnancy trimesters.Then a total of 1430 cases of pregnant women receiving routine prenatal examination from Chongzhou People's Hospital were collected during November,2017 and December 2018.The serum TSH values collected for each pregnant woman in this study were taken as the standard value.The reference range for pregnancy trimesters-specific serum TSH recommended by ATA guideline in 2017 and the reference range set up by the Laboratory Department of the hospital in this study upon the recommendations of Simens(Germany)for the serum TSH of non-pregnant women to test whether the serum TSH values obtained through the current study fit the diagnosis of hypothyroidism during pregnancy.Results:(1)The median and 95% confidence interval for serum TSH during the first trimester are 1.24 mIU/L(0.22-4.21mIU/L);the median and 95% confidence interval for serum TSH during the second trimester are 1.62 mIU/L(0.17-4.36mIU/L);the median and 95% confidence interval for serum TSH during the second trimester are 2.47 mIU/L(0.34-4.64mIU/L).(2)Using the reference range for pregnancy trimesters-specific serum TSH proposed by ATA(American Thyroid Association)in 2017 Guideline,the reference range established by this study for pregnant women and the reference range established by Chongzhou People's Hospital for non-pregnant women,the prevalence rate of hypothyroidism among the 1430 selected pregnant women were 11.7%(168/1430),6.9%(99/1430),and 1.9%(27/1430).(3)Consistency rate between hypothyroidism diagnosed using the reference range recommended in ATA Guideline in 2017 and hypothyroidism diagnosed using the reference range established in the current study is 83.9%.The consistency rate between hypothyroidism diagnosed using the reference range established by the studied hospital for non-pregnant women and the reference established in the current study is 79.6%.Conclusion:(1)Serum TSH value is lowest during the first trimester of pregnancy.(2)The prevalence rate obtained using the TSH reference range established by this study to diagnose hypothyroidism during pregnancies was generally consistent with other domestic reports.(3)The prevalence rate obtained using the reference range recommended by ATA in its 2017 guideline was higher than the prevalence range obtained using the reference range for TSH during pregnancies established in the current study.Therefore,it is recommended that hospitals and laboratories should establish their own reference range for pregnant women's TSH.(4)Using the reference range of TSH for non-pregnant women could potentially lead to misdiagnosis and missed diagnosis of.Therefore,it is very important for hospitals and laboratories to formulate reference ranges that are specific to pregnant women.