Search

Objective We evaluated the intraday changes of thyroid function biomarkers in healthy subjects to help clinicians diagnose thyroid diseases in appropriate timing. Methods Blood samples were collected from 31 subjects at 0:00, 4:00, 8:00, 12:00, 16:00 and 20:00 on the sampling day and analyzed for thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4). The intraday concentration changes were analyzed using Friedman's 2-way analysis of variance by ranks. Results The concentrations of TSH, T3, T4, FT3, and FT4 in males were significantly higher than those in females (P  < .01). The obvious peak circadian rhythm of TSH was observed at 0:00 AM with gradual decline thereafter, whereas other biomarkers showed no rhythmic changes. Conclusion Sex differences should be considered in interpreting thyroid function tests. It is important to select the sampling time according to the clinician's diagnostic needs, especially at night when TSH secretion peaks. [ABSTRACT FROM AUTHOR]

Aims: To correlate glycated albumin (GA) and glycosylated haemoglobin (HbA1c) and establish a novel formula for estimating HbA1c from GA.Methods: We retrospectively enrolled 20,381 cases and excluded HbA1c and GA outliers by residual analysis. HbA1c ranged from 4.0-12.0% and GA from 7.5-45%. The HbA1c range of 4.0-8.0% in both sexes was stratified into eight groups with an increase of 0.5%, and the means of GA and HbA1c were compared. HbA1c was divided into 38 groups with increments of 0.1% (range, 4.3-8.0%), and the correlation between HbA1c and GA was investigated.Results: There was no significant sex-based difference between HbA1c and GA. The analysis showed that when HbA1c was 6.2% or GA was 12.28%, the linear relationship between the two parameters was not continuous. When HbA1c was <6.2% or GA < 12.28%, we devised the formula: HbA1c = 1.136 × GA - 7.289 (R2 = 0.824). For HbA1c ≥ 6.2% or GA ≥ 12.28%, the equation was: HbA1c = 0.252 × GA + 3.163 (R2 = 0.948).Conclusion: A discontinuous linear relationship exists between HbA1c and GA when HbA1c is 6.2% or GA is 12.28%, although with a significant turning point. The GA value can be used to estimate the HbA1c value with the two regression equations to accurately estimate the long-term average blood glucose level of patients. [ABSTRACT FROM AUTHOR]