The incidence of thyroid cancer has increased globally and in Denmark. Following total thyroidectomy, patients at intermediate or high risk undergo radioactive iodine (RAI) therapy with [131]I to ablate residual thyroid tissue and treat potential metastases. European and American guidelines recommend post-treatment whole-body scintigraphy (WBS) 2-10 days after RAI to supply information on disease staging. This study evaluated whether post-treatment [131]I WBS findings influenced subsequent clinical management for the patients. In this retrospective cohort study, 363 patients received RAI at Herlev University Hospital between January, 2021, and February, 2024. Post-treatment [131]I WBS was available in 330 patients (91% - the study group). In a subgroup analysis, patients with negative scans, known metastases, or prior RAI therapy were excluded. Medical records were reviewed to determine whether WBS findings led to changes in management, defined as additional RAI therapy, supplementary imaging, or modification of follow-up. Among the 330 patients, 249 (76%) high-risk patients received 3.7 GBq, 80 (24%) intermediate-risk patients received 1.1 GBq, and one pediatric patient received 2.0 GBq. No intermediate-risk patients showed iodine-avid foci beyond residual neck uptake. Among the 298 patients who received adjuvant RAI without known metastatic disease, 15 had suspected metastases on WBS, of whom only six (2%) experienced a management change. ost-treatment [131]I WBS rarely influenced decision-making, affecting only 2% of adjuvant RAI patients. Given the overall good prognosis and limited clinical impact, the routine use of post-treatment [131]I WBS, particularly in intermediate-risk patients, may warrant reconsideration in future guidelines.

In clinical practice, patient follow-up requires scans to be performed on the same densitometer to ensure comparability. This study evaluated the agreement and equivalence between nine Lunar iDXA and four Lunar Prodigy scanners, assessing their interchangeability for longitudinal spine BMD monitoring. The manufacturer's encapsulated spine phantom was scanned 15 times on each of nine iDXA and four Prodigy densitometers under routine quality-control conditions by a single experienced operator. For each scanner, L2-L4 BMD repeatability was assessed using mean, SD, and coefficient of variation. Between-scanner equivalence was tested pairwise using two one-sided tests with ±1% equivalence bounds with Holm-Bonferroni correction. Exploratory method-comparison plots were used to assess agreement across vertebral regions. All iDXA scanners demonstrated low within-scanner variability (CV: 0.07-0.23%) and closely clustered mean BMD values, with a small negative bias relative to the phantom nominal value (mean -0.63%). All pairwise iDXA comparisons met the predefined ±1% equivalence criterion. Graphical analyses confirmed high agreement across all vertebral levels. In contrast, Prodigy scanners showed higher variability (CV: 0.17-0.33%), a positive bias (mean +1.5%), and failed to meet equivalence criteria in most pairwise comparisons. Under the conditions of this phantom study, the nine iDXA scanners in the region showed high agreement and may be sufficiently equivalent for longitudinal spine BMD monitoring across different sites. However, the Prodigy scanners did not demonstrate sufficient agreement for interchangeable use. These findings support regional harmonization of iDXA-based BMD measurements, although validation in vivo, including femoral and full-body measurements, is warranted.

To evaluate whether long-term IQC-derived analytical variability of serum creatinine (SCr), even within allowable limits, is associated with estimated glomerular filtration rate (eGFR)-based chronic kidney disease (CKD) staging consistency and stage reclassification. This single-center retrospective study included 4,215 patients with stable kidney function and 10,481 SCr records from 2022-2024. Daily relative analytical deviation was estimated using a 5-day moving median of IQC results. After analytical-deviation adjustment, eGFR was recalculated using the 2021 CKD-EPI equation and CKD stages were reassigned. Reclassification was defined as stage inconsistency before versus after adjustment. Associated factors were analyzed using multivariable generalized estimating equation logistic regression. All IQC-derived analytical deviations remained within the CLIA 2025 limit (±10%). Positive deviation occurred in 89.2% of records, and 31.6% had an absolute deviation ≥ 5%. Overall, 5.3% (559/10,481) of records were reclassified, with 98.2% shifting from higher-risk to lower-risk CKD stages. Reclassification rates for CKD stages G3a, G3b, and G4 were 12.73%, 19.48%, and 44.44%, respectively. Each 1% increase in analytical-deviation magnitude was associated with higher reclassification risk (aOR = 1.39, 95% CI: 1.34-1.43, p < 0.001), whereas reagent change within 30 days was not significant. Within permissible limits, long-term IQC-derived analytical deviation of SCr assays is significantly associated with CKD stage reclassification, especially near eGFR decision thresholds. Positive IQC-derived analytical deviation was associated with a higher likelihood of apparent CKD stage overestimation. These findings inform quality control and eGFR interpretation, but generalizability requires multicenter prospective validation.

We have previously developed a potential non-invasive fibrosis marker in the form of a lectin immunoassay for the detection of fucosylated α1-acid glycoprotein in plasma (P-AGP-FR). We aimed to investigate the diagnostic accuracy of P-AGP-FR for liver cirrhosis and fibrosis in a clinical setting of patients with chronic viral hepatitis. One hundred twenty-four patients, 80 with chronic hepatitis B and 44 with chronic hepatitis C, were recruited at two centers. P-AGP-FR levels were evaluated in relation to fibrosis or cirrhosis according to liver biopsy or transient elastography, and its diagnostic accuracy was compared with other noninvasive biochemical fibrosis markers; APRI and FIB-4. AGP fucosylation was elevated in patients with fibrosis, and the correlation of P-AGP-FR values with fibrosis levels was significant in all groups. The probability for fibrosis increased with higher P-AGP-FR values, with an odds ratio (OR) of 2.79. Receiver operating characteristic (ROC) curve analysis was done for the diagnostic accuracy of P-AGP-FR for fibrosis according to biopsy and liver elastography, respectively. Area under the ROC curve (AUROC) was 0.74 (95% CI: 0.58-0.91) for fibrosis according to biopsy and 0.72 (95% CI: 0.58-0.85) for fibrosis according to liver elastography. Optimal cutoff by Youden for fibrosis according to liver biopsy was 1.95, sensitivity 63.6% and specificity 85.7%. For fibrosis according to liver elastography, optimal cutoff was 1.44, sensitivity 54.6% and specificity 78.8%. In conclusion, AGP fucosylation measured as P-AGP-FR was significantly higher in patients with hepatic fibrosis and cirrhosis, and we found a significant correlation between P-AGP-FR and fibrosis stage.

To review methods for graphical illustration of paired comparisons in the pretest-posttest design and present a new and simple plot, based on the waterfall plot combined with evaluation of vertical symmetry. The plot includes changes in the raw data, median changes with confidence zones and allows easy visualization of correction for regression to the mean to guide subsequent analysis of covariance or mixed effects modeling and for final presentation. The methods are demonstrated using a publicly available clinical dataset and simulations of illustrative example data performed in R. Compared to previous methods such as 1) the simple scatter plot of pretest vs. change, 2) the tilted line-segment plot, 3) Galton's squeeze plot, and 4) a one-dimensional scatter plot, the waterfall plots have several advantages: no overlap of data, ease of interpretation, independence of sample size, and the ability to clearly visualize regression to the mean and a possible intervention effect. The combination of vertical symmetry, waterfall plots, box plot summaries, and confidence zones allows for quick decoding and comparison of pre- and post-test data. This approach effectively visualizes and helps evaluate the occurrence of regression to the mean and/or a possible intervention effect, regardless of sample size.

Estimated glomerular filtration rate (eGFR) serves as an overall indicator of kidney health. A sustained value below 60 mL/min/1.73 m[2] for more than 3 months confirms a diagnosis of chronic kidney disease. The same decision limit is used for patients at all ages. This may not be ideal, however, because eGFR decreases with age in healthy individuals above 40 years of age. Evidence suggests that percentile charts for eGFR could have clinical value. We used a so-called indirect method with production data to construct percentiles of serum creatinine levels in healthy white Europeans aged 2 to 84 years. These percentiles were converted into eGFR values to construct percentile charts for the European eGFREKFC. Between ages 20 and 84, our curves differ somewhat from a recent study of healthy European adults, whereas the curves for ages 6-12 align more closely with a recent study of healthy European children.

When blood samples for biochemical tests are collected outside the hospital the transport to the laboratory is dependent on timetables and routines of the transport companies. From islands not connected to the mainland by bridge transport is challenged and the needs of acute tests might be practically impossible to fulfill. In such situations, use of unmanned drones has great potential. In this study, a total of 19 drone flights were performed on three days in February and four days in August with an average flight time of 36 min. In blood samples from healthy volunteers (51 in February and 60 in August) we compared the results of 32 routine parameters and serum indices obtained in three identical sets of samples that were either flown by drone, driven by car or stored in the laboratory. Plasma LDH was found to increase significantly when tubes, both with and without separation gel, were transported by drone, and in August also in tubes without separation gel transported by car. The remaining tests were not affected significantly by transportation. Therefore, regulations in aviation are the major obstacles for transportation of blood samples by drones, and not the influence on analytical results. Further, we found that separation gel in itself caused increased levels of hemolysis index, LDH, potassium and phosphate, which for the latter two tests exceed our acceptance criteria as well as the impact of sample transport by drone or by car.

HbA1c is a key biomarker for diagnosing and monitoring diabetes, but its reliability may be affected by preanalytical conditions, including sample storage. This study evaluated the stability of HbA1c in whole-blood EDTA samples stored at 2-8 °C. A pooled blood sample from 65 anonymized leftover specimens was aliquoted and measured in triplicate using capillary electrophoresis (Minicap Flex Piercing, Sebia) over 20 days, with an additional measurement at day 35. Total Allowable Error (TEa ±4.9%) and Reference Change Value (RCV ±2.32 mmol/mol) were used to determine molecular stability. HbA1c remained analytically stable for up to 13 days in this specific setting. This finding, when validated in different conditions, may help laboratories to optimize the routine workflow.

Reliable reference limits for hematological parameters are essential for clinical interpretation. In this study, we estimated reference limits for hemoglobin, erythrocytes and MCH using direct and indirect methods on data from the Trøndelag Health Study (HUNT). Results from 53,591 men and non-pregnant women participating in HUNT4 survey were used to estimate reference limits using two indirect methods (refineR and TMC13). A healthy defined subset of 15,755 participants (29%) was used to establish reference limits using the direct method. Reference limits were estimated separately for men and women in three age groups. Due to limited sample size, only direct estimates were generated for participants ≥80 years. Among women the estimated 2.5 percentile of hemoglobin, using the direct method, was 119 g/L in those aged 19-49 years and 122 g/L in those aged 50-79 years. Corresponding estimates from the indirect methods were 120 and 121 g/L in women aged 19-49 years and 121 g/L in those aged 50-79 years. In men aged 19-49 years, all methods estimated the 2.5 percentile of hemoglobin at 137 g/L. In men aged 50-79 years the direct estimate was 135 g/L, while indirect methods estimated slightly lower values (132 and 133 g/L). Overall, indirect and direct estimates were largely consistent, with some exceptions. The observed age-related variation in reference limits for both sexes supports the need for age-specific reference intervals. We propose revised reference limits for hemoglobin based on these findings.

Shrunken Pore Syndrome (SPS), an eGFRcys/eGFRcr ratio < 0.6, is hypothesized to reflect selective glomerular filtration discordance, though its mechanism remains debated. Because an informative biomarker should associate with mechanistically related outcomes but not unrelated ones, we tested whether the continuous eGFRcys/eGFRcr ratio is selectively associated with hyperuricemia (HUA) but not elevated fasting glucose (IFG, a negative control). Routine fasting data from 29,534 health-examination adults were analyzed; eGFR was estimated using the CKD-EPI 2021 creatinine and 2012 cystatin C equations. HUA (primary outcome) and IFG (≥6.1 mmol/L) were modeled by multivariable logistic regression adjusted for age, sex, lipids and absolute eGFRcr, with pre-specified propensity-score matching (PSM) on age, sex and eGFRcr and a strict-IFG analysis excluding diabetes. HUA occurred in 6,632 participants (22.5%), IFG in 2,760 (9.3%) and binary SPS in 241 (0.82%). Each 0.1-unit ratio decrease raised HUA odds by 38% (OR 1.38, 95% CI 1.35-1.42; lowest-vs-highest quartile OR 2.83), whereas the IFG association was null (OR 1.03, p = 0.127). In the eGFRcr-matched PSM cohort excluding diabetes, SPS remained associated with HUA (OR 2.30, p < 0.001) but not strict IFG (OR 1.28, p = 0.29); findings were robust across tertile, spline, TyG-adjusted and age-stratified analyses. The eGFRcys/eGFRcr ratio is therefore graded-associated with hyperuricemia but not fasting glucose, supporting its interpretation as a phenotypic marker of selective glomerular filtration discordance rather than a generic metabolic-risk index. Prospective validation is required.

By necessity, a wrongly estimated pretest probability leads to a wrongly estimated posttest probability, even for correctly interpreted quantitative diagnostic test results. The effect of wrongly estimated pretest probability on the clinical utility of quantitative test results is unknown. We simulated test results from one real and two imaginary, quantitative diagnostic tests to study this issue for specific values of benefit and cost of treatment. We found that a wrongly estimated pretest probability reduces the clinical utility of a correctly interpreted quantitative diagnostic test result and may, in extreme cases, cause harm to the patient.