The impact of time of sample collection on the measurement of thyroid stimulating hormone values in the serum

Mirjanic-Azaric, Bosa; Stojakovic-Jelisavac, Tanja; Vukovic, Blazenko; Stojanovic, Darja; Vujnic, Milorad; Uletilović, Snežana

doi:10.1016/j.clinbiochem.2015.08.020

Cited by 22 publications

(18 citation statements)

References 13 publications

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“…A limiting factor could be that the sampling time is not standardized, as pointed out in the study of Mirjanic- Azaric et al (28). Further, it is known from the Middle Ages that the Balkan region is strumogenic, and recent researches in the Republic of Srpska (29) indicated a lack of iodine in the diet, which could certainly affect some reference values for TSH in the Republic of Srpska.…”

Section: Discussionmentioning

confidence: 99%

Direct Estimation of Reference Intervals for Thyroid Parameters in the Republic of Srpska

Mirjanic-Azaric

Avram

Stojakovic-Jelisavac

et al. 2017

Journal of Medical Biochemistry

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summaryBackgroundThe aim of this study was to determine the reference values for thyrotropin (TSH), thyroid hormones (total and free thyroxine, T4 and fT4; total and free triiodothyronine, T3 and fT3), thyroglobulin (Tg) and thyroid antibodies (thyroid peroxidase, TPOAb and thyroglobulin antibody, TgAb) in the population of the Republic of Srpska.MethodsA total of 250 euthyroid subjects were enrolled in this study. A direct method for choosing reference subjects was used to establish reference intervals. The hormones and thyroid antibodies were measured by an electrochemiluminescence immunoassay method (ECLIA, Roche Diagnostics, Mannheim, Germany). We calculated the reference intervals by MedCalc, version 12.1.4.0 (MedCalc software, Belgium) as recommended by the IFCC (CLSI C28-A3).ResultsUsing guidelines recommended by the National Academy of Clinical Biochemistry (NACB) and based on standard statistical approaches, the reference intervals derived for TSH, fT4, T4, fT3, T3 were 0.75–5.32 mIU/L, 12.29–20.03 pmol/L, 73.49–126,30 nmol/L, 4.11–6.32 pmol/L, 1.15–2.32 nmol/L and for Tg, TPOAb, TgAb were 3.63–26.00 μg/L, <18.02 mIU/L, < 98.00 mIU/L, respectively. We found a significant difference (p<0.05) in TSH and fT3 values between different age groups as well as in T4, fT4 and fT3 values between ge nder groups.ConclusionsThe established reference values for the population of the Republic of Srpska were significantly different from the values recommended by the manufacturer of reagents (Roche Diagnostics). Our results showed that a laboratory needs to establish its own reference values in order to set up a proper diagnosis, as well as to treat patients successfully.

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Section: Discussionmentioning

confidence: 99%

Direct Estimation of Reference Intervals for Thyroid Parameters in the Republic of Srpska

Mirjanic-Azaric

Avram

Stojakovic-Jelisavac

et al. 2017

Journal of Medical Biochemistry

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“…The greatest impact on variations in serum TSH concentrations has been observed for the sampling time ( 25 , 26 ), which is caused by the circadian rhythm of TSH. This daily cycle of 24 h is driven by the biological clock of the suprachiasmatic nucleus (SCN).…”

Section: Sources Of Within-person Variation In Tsh Levelsmentioning

confidence: 99%

Within-Person Variation in Serum Thyrotropin Concentrations: Main Sources, Potential Underlying Biological Mechanisms, and Clinical Implications

2021

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BackgroundIndividuals exhibit fluctuations in the concentration of serum thyroid-stimulating hormone (TSH) over time. The scale of these variations ranges from minutes to hours, and from months to years. The main factors contributing to the observed within-person fluctuations in serum TSH comprise pulsatile secretion, circadian rhythm, seasonality, and ageing. In clinical practice and clinical research however, such within-person biological variation in serum TSH concentrations is often not considered. The aim of this review is to present an overview of the main sources of within-person variation in TSH levels, as well as the potential underlying biological mechanisms, and the clinical implications.SummaryIn euthyroid individuals, the circadian rhythm, with a nocturnal surge around 02:00–04:00 h and a nadir during daytime has the greatest impact on variations in serum TSH concentrations. Another source of within-person variation in TSH levels is seasonality, with generally higher levels during the cold winter months. Since TSH is secreted in a pulsatile manner, TSH levels also fluctuate over minutes. Furthermore, elevated TSH levels have been observed with ageing. Other factors that affect TSH levels include thyroid peroxidase (TPO)-antibody positivity, BMI, obesity, smoking, critical illness, and many xenobiotics, including environmental pollutants and drugs. Potential underlying biological mechanisms of within-person variation in TSH levels can be safely concluded from the ability of TSH to respond quickly to changes in cues from the internal or external environment in order to maintain homeostasis. Such cues include the biological clock, environmental temperature, and length of day. The observed increase in TSH level with ageing can be explained at a population level and at an organism level. In clinical practice, the season for thyroid testing can influence a patient’s test result and it occurs frequently that subclinical hypothyroid patients normalize to euthyroid levels over time without intervention.ConclusionsSerum TSH concentrations vary over time within an individual, which is caused by multiple different internal and external factors. It is important to take the within-person variations in serum TSH concentrations into account when testing a patient in clinical practice, but also in performing clinical research.

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“…Було проведено дослідження рівнів ТТГ у волонтерів за різних умов обстеження (натще/після їжі і в різний час зранку) [1]:…”

Section: тиреотропний гормон: важливі фактори впливу які потрібно врunclassified

Тиреотропний Гормон: Важливі Фактори Впливу, Які Потрібно Врахувати

Rykova¹

2021

Mìžnarodnij endokrinologìčnij žurnal

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Методичні рекомендації /Methodical Recomendations/ Що потрібно враховувати при визначенні рівнів тиреотропного гормону? Урахування добової варіабельності тиреотропного гормону (ТТГ) Відомо, що в цього гіпофізарного гормону:-максимальні рівні спостерігаються в нічні години, у середньому в період з 02:00 до 04:00;-мінімальні рівні спостерігаються в другій половині дня, у середньому в період з 14:00 до 16:00. Амплітуда коливань залежить від індивідуальних характеристик людини, наявності чи відсутності патології щитоподібної залози, захворювань, що впливають на рівні тиреоїдних гормонів, у тому числі перетворення Т 4 у Т 3. Згідно з даними різних досліджень, добові коливання рівнів ТТГ можуть становити до 140-220 %. А це значний відсоток, що може суттєво вплинути на результати, які ми отримаємо в людини. У першу чергу це стосується тих пацієнтів, у яких рівень ТТГ коливається близько верхньої

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The impact of time of sample collection on the measurement of thyroid stimulating hormone values in the serum

Cited by 22 publications

References 13 publications

Direct Estimation of Reference Intervals for Thyroid Parameters in the Republic of Srpska

Direct Estimation of Reference Intervals for Thyroid Parameters in the Republic of Srpska

Within-Person Variation in Serum Thyrotropin Concentrations: Main Sources, Potential Underlying Biological Mechanisms, and Clinical Implications

Тиреотропний Гормон: Важливі Фактори Впливу, Які Потрібно Врахувати

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