Resting time and diurnal variation: TSH misclassification by time of day
Andersen IB, Brasen CL, Christensen H, Noehr-Jensen L, Nielsen DE, Brandslund I, Madsen JS
The finding, in our words
In 20,019 outpatient TSH samples drawn between 07:00 and 15:00, mean TSH fell from 2.76 mIU/L at 07:00-09:00 to 2.22 mIU/L at 13:00-15:00, about 28% across the day, with the steepest decline before 09:00. Against the 4.0 mIU/L upper reference limit, 14.1% of patients were above it at 07:00-08:00 and 7.9% at 14:00-15:00, so 6.2% changed side of the decision limit on sampling time alone. Resting time before sampling had no clinically significant effect on TSH, albumin, calcium or sodium.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
A 3D-printed microsampling device extracted 80% plasma from 20 μL of whole blood while removing more than 93% of hemoglobin interference. The device demonstrated linearity, accuracy and precision suitable for hCG analysis according to EMA guidelines, offering a robust tool for point-of-care diagnostics that enhances analytical sensitivity and specificity.
Mrsa et al., Journal of proteome research (paywalled) · source ↗
A 2025 review maps 28 microsampling devices, from dried spots and volumetric absorptive tips to upper-arm liquid capillary collectors, and names what a laboratory must control before their results are used: the haematocrit effect in non-volumetric dried samples, interstitial fluid from finger milking, volume, haemolysis and transport stability. Regulators on both sides of the Atlantic ask for the same two things, a device the patient can use safely and a sample fit for the test.
Task-force guideline on optimising levothyroxine monotherapy. After a change of dose it advises measuring free T4 and TSH at six weeks. It attributes the slow response to the long half-life of T4 and the delayed TSH reaction without giving either a number. On dosing routine, taking the tablet with breakfast produced the highest and most variable TSH of three regimens, while an hour before breakfast or at bedtime kept TSH inside the reference interval.
Centanni M, Duntas L, Feldt-Rasmussen U, Koehrle J, Peeters RP, Razvi S, Trimboli P, Virili C, European Thyroid Journal · source ↗
A US survey of 3,400 adults aged 62 to 90 collected up to 15 biomeasures at home, including saliva, dried blood spots and urine, with Salivette and Oragene among the devices used, which shows that several patient-centric sampling methods can run together in home-based research.
Jaszczak et al., The journals of gerontology. Series B, Psychological sciences and social sciences (paywalled) · source ↗
The analysis indicates that dried blood spots and volumetric absorptive microsampling enable minimally invasive monitoring of prohibited substances, with volumetric absorptive microsampling offering improved quantitative reliability over traditional dried spots.