The diurnal change of thyroid-stimulating hormone and the effect of this change on thyroid functions in patients with chronic kidney disease.

PURPOSE: Thyroid-stimulating hormone (TSH) has a pulsatile and circadian rhythm in healthy individuals. We aimed to evaluate the diurnal changes of free thyroid hormones and serum TSH levels in patients with end-stage renal failure (ESRF) whose thyroidal functions are at normal ranges. METHODS: Thirty hemodialysis patients with chronic renal failure and without a known thyroidal disease who are over 18 and 35 healthy individuals were included. The serum TSH, free T3, and free T4 levels were examined among the patient and control group which were taken at 8:00 a.m., 4:00 p.m., and 0:00 a.m. RESULTS: Twenty-two (73.3%) patients were male, and the mean age of the patient group was 64 (sd = 14.45 years). Seventeen (48.6%) of the control group were female, and the mean age was 31.9 (sd = 6.4 years). Serum free T3 levels, measured at three different time points (8:00 a.m., 4:00 p.m., and 0:00 a.m.), were significantly lower in the patient group than in the control group and serum free T4 levels were measured at three different time points (8:00 am, 4:00 p.m., and 0:00 a.m.) were significantly higher in the patient group than in the control group. Serum TSH levels were higher in the patient group than in the control group at 08:00, and were lower at 24:00 (p < 0.001). The nocturnal increase of serum TSH level under 0.525 suggested diurnal rhythm disruption with 83% sensitivity and 87% specificity. CONCLUSION: The nocturnal serum TSH increase is not seen in ESRF patients who did not have a thyroid disease. We think that not observing a nocturnal TSH increase could be an early indication of the sick euthyroid syndrome.

The response of total testing process in clinical laboratory medicine to COVID-19pandemic.

INTRODUCTION: Following a pandemic, laboratory medicine is vulnerable to laboratory errors due to the stressful and high workloads. We aimed to examine how laboratory errors may arise from factors, e.g., flexible working order, staff displacement, changes in the number of tests, and samples will reflect on the total test process (TTP) during the pandemic period. MATERIALS AND METHODS: In 12 months, 6 months before and during the pandemic, laboratory errors were assessed via quality indicators (QIs) related to TTP phases. QIs were grouped as pre-, intra- and postanalytical. The results of QIs were expressed in defect percentages and sigma, evaluated with 3 levels of performance quality: 25th, 50th and 75th percentile values. RESULTS: When the pre- and during pandemic periods were compared, the sigma value of the samples not received was significantly lower in pre-pandemic group than during pandemic group (4.7σ vs. 5.4σ, P = 0.003). The sigma values of samples transported inappropriately and haemolysed samples were significantly higher in pre-pandemic period than during pandemic (5.0σ vs. 4.9σ, 4.3σ vs. 4.1σ; P = 0.046 and P = 0.044, respectively). Sigma value of tests with inappropriate IQC performances was lower during pandemic compared to the pre-pandemic period (3.3σ vs. 3.2σ, P = 0.081). Sigma value of the reports delivered outside the specified time was higher during pandemic than pre-pandemic period (3.0σ vs. 3.1σ, P = 0.030). CONCLUSION: In all TTP phases, some quality indicators improved while others regressed during the pandemic period. It was observed that preanalytical phase was affected more by the pandemic.