Interpretation of TSH results can be improved by reference values fluctuating in time.

Objectives: The secretion of thyroid stimulating hormone (thyrotropin, TSH), is characterized by a marked circadian rhythm. Plasma or serum TSH values are significantly lower in the afternoon and in the evening as compared to the early morning. As in clinical practice, blood sampling time shows an important variation, a reliable assessment of thyroid status is often not an easy task for the clinician.

Colorimetric correcting for sample concentration in stool samples.

Objectives: Fecal immunochemical tests (FIT) for hemoglobin are currently considered the screening investigation of choice for colorectal cancer and are worldwide recommended. Similarly, fecal calprotectin is a widely used test for monitoring intestinal inflammation. The pre-analytical issues regarding stool samples have hardly been dealt with and are difficult to solve.

Factors to take into account when interpreting 25-hydroxy-vitamin D serum levels.

Background: Assessing vitamin D status, typically evaluated using serum or plasma 25-hydroxy vitamin D [25(OH)D] concentration, is complex because of various influencing factors.

Methods: Seasonality significantly affects intra-individual variability in 25(OH)D levels. This variation can be addressed by employing cosinor functions that are tailored to the geographical location of the patient to correct for seasonal effects.

HOMA-IR and HOMA2-IR estimation based on glycated hemoglobin as an alternative for fasting glucose.

Background: Diabetes mellitus is a major global public health problem. Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) is a key laboratory index in the assessment of insulin resistance. The calculation of HOMA-IR and its updated version HOMA2-IR are partly based on plasma glucose determinations, which are prone to important pre-analytical errors.

Laying the foundation for enhancing safety of desmopressin in older people: Validation of capillary blood sodium levels.

Purpose: We aim to make desmopressin a safe treatment option for (older) patients at risk for hyponatremia, by introducing a new way of sodium monitoring. The goal is to reduce the risk of hyponatremia, enhance patient safety and ultimately introduce self-monitoring of sodium levels. The first step in the aforementioned is to validate capillary sodium.