Clinically Relevant Laboratory Monitoring of Gender-Affirming Hormone Therapy in Transgender People-Experiences from a Teaching Hospital in the Netherlands.

BACKGROUND: Transgender care is shifting from academic to nonacademic settings leading to use of common (immunoassay) compared to sophisticated (mass spectrometry) methods to monitor estradiol and testosterone during gender-affirming hormone therapy (GAHT). The type of assay can influence results and have significant implications for clinical decision making. An evidence gap is present in recommendations regarding the assay needed to monitor GAHT. The present study aimed to summarize current evidence and evaluate immunoassay estradiol and testosterone concentrations in transgender people visiting a nonacademic hospital for GAHT. METHODS: Clinical practice guidelines on GAHT and scientific literature on assay methodologies were screened and summarized. Laboratory and medical data from 252 patients who visited the transgender outpatient clinic of the Maasstad Hospital for GAHT between 2020 and 2022 were retrospectively analyzed. RESULTS: Our research showed that the most used clinical practice guidelines for GAHT provide hormonal target values without recommending a preferred method. A comprehensive literature search on agreement between immunoassay and mass spectrometry showed substantial heterogeneity in results. Retrospective analysis of our immunoassay measured data in transgender people showed hormonal changes during GAHT that are to be expected from the medication used. CONCLUSIONS: We demonstrate that laboratory monitoring of GAHT in a nonacademic hospital can be done safely by immunoassay in most cases. Only in cases where clinical observation is discordant with the hormonal results do more sophisticated methods need to be deployed. A best practice model was proposed for transgender care in nonacademic hospitals.

Assessment of Comorbidity in Bariatric Patients through a Biomarker-Based Model-A Multicenter Validation of the Metabolic Health Index.

BACKGROUND: The metabolic health index (MHI) is a biomarker-based model that objectively assesses the cumulative impact of comorbidities type 2 diabetes mellitus, hypertension and dyslipidemia on the health state of bariatric patients. The MHI was developed on a single-center cohort using a fully laboratory data-driven approach, resulting in a MHI score on a range from 1 to 6. To show universal applicability in clinical care, the MHI was validated externally and potential laboratory-related shortcomings were evaluated. METHODS: Retrospective laboratory and national bariatric quality registry data were collected from five Dutch renowned bariatric centers (n = 11 501). MHI imprecision was derived from the cumulative effect of biological and analytical variance of the individual input variables of the MHI model. The performance of the MHI (model) was assessed in terms of discrimination and calibration. RESULTS: The cumulative imprecision in MHI was 0.25 MHI points. Calibration of the MHI model diverged over the different centers but was accounted for by misregistration of comorbidity after cross-checking the data. Discriminative performance of the MHI model was consistent across the different centers. CONCLUSIONS: The MHI model can be applied in clinical practice of bariatric centers, regardless of patient mix and analytical platform. Because the MHI is based on objective parameters, it is insensitive to diverging clinical definitions of comorbidities. Therefore, the MHI can be used to objectify severity of metabolic comorbidities in bariatric patients. The MHI can support the patient-selection process for surgery and objectively assessing the effect of surgery on the metabolic health state.

Impact of Thyroglobulin and Thyroglobulin Antibody Assay Performance on the Differential Classification of DTC Patients.

CONTEXT: Measurements of thyroglobulin (Tg) and Tg antibodies are crucial in the follow-up of treated differentiated thyroid cancer (DTC) patients. Interassay differences may significantly impact follow-up. OBJECTIVE: The aim of this multicenter study was to explore the impact of Tg and Tg antibody assay performance on the differential classification of DTC patients, as described in national and international guidelines. DESIGN: Four commonly used Tg and Tg antibody assays were technically compared to reflect possible effects on patients with DTC follow-up. Storage stability at different storage temperatures was also investigated for LIAISON® and Kryptor assays, as this is an underexposed topic in current literature. RESULTS: B.R.A.H.M.S. assays yield approximately 50% lower Tg values over the whole range compared to the DiaSorin and Roche assays investigated. These differences between assays may result in potential misclassification in up to 7% of patients if fixed cutoffs (eg, 1 ng/mL) are applied. Poor correlation was also observed between the Tg antibody assays when the method-specific upper limits of normal are used as cutoffs. Storage of Tg and Tg antibodies was possible for 3 to 4 weeks at -20°C and -80°C. Calibration of the assays, however, was found to be crucial for stable results over time. CONCLUSIONS: Technical aspects of Tg and Tg antibody assays, including interassay differences, calibration and standardization, and cutoff values, may have a significant clinical impact on the follow-up of DTC patients.

Clinical Guidelines and PTH Measurement: Does Assay Generation Matter?

PTH is an important regulator of calcium and phosphate homeostasis and bone remodeling. It is metabolized into PTH fragments, which are measured to a different extent by PTH assays of different generations because of differences in fragments recognized and lack of assay standardization. PTH is measured in the workup of several conditions, and clinical guidelines provide recommendations concerning these measurements. This review provides an overview of the impact of differences between PTH assays, applying distinct clinical guidelines for primary and secondary hyperparathyroidism and perioperative use of PTH measurements. Guidelines deal with PTH measurement in different ways, recommending either trend monitoring, the use of a fold increase of the upper reference limit, or an absolute PTH cutoff value. For classic primary hyperparathyroidism (PHPT), the type of PTH assay used will not affect diagnosis or management because the precise concentration of PTH is less relevant. In chronic kidney disease, the guideline recommends treating secondary hyperparathyroidism above a twofold to ninefold PTH increase, which will result in different clinical decisions depending on the assay used. For patients after bariatric surgery, guidelines state absolute cutoff values for PTH, but the impact of different generation assays is unknown because direct comparison of PTH assays has never been performed. During parathyroid surgery, PTH measurements with a third-generation assay reflect treatment success more rapidly than second-generation assays. Increased awareness among clinicians regarding the complexity of PTH measurements is warranted because it can affect clinical decisions.

Potential usefulness of inflammatory markers to monitor respiratory functional impairment in sarcoidosis.

BACKGROUND: Sarcoidosis is a multiorgan inflammatory granulomatous disorder of unknown origin for which adequate markers to monitor disease severity are lacking. The aim of this study was to evaluate the potential clinical usefulness of serologic markers of inflammation [high-sensitivity C-reactive protein (hs-CRP) and serum amyloid A (SAA)], T-cell activation [soluble interleukin-2 receptor (sIL2R)], and granuloma formation [angiotensin-converting enzyme (ACE)] for monitoring of sarcoidosis. METHODS: Of the 185 sarcoidosis patients who visited the Sarcoidosis Management Center between 1999 and 2002, we selected 144 nonsmoking patients: 73 untreated (group I) and 71 treated (group II). Subgroups of the untreated patients [group Ia (nonchronic group with time since diagnosis < or = 2 years) and group Ib (chronic group with time since diagnosis >2 years)] were evaluated separately. ROC curves and logistic regression analyses were used to compare the diagnostic accuracy of different markers to assess disease severity. Pulmonary disease severity was defined by lung function test results. RESULTS: In untreated subgroup Ia and the total untreated group (group I), sIL2R had the largest areas under the curves (AUCs; 0.891 and 0.799, respectively) and the highest sensitivity (82% and 64%), specificity (94% and 88%), and positive (82% and 70%) and negative (94% and 88%) predictive values among the evaluated markers in both untreated groups. Nevertheless, the confidence intervals for sIL2R AUC, sensitivity, and specificity were broad and partly overlapped those of ACE, hs-CRP, and SAA. In the treated group (group II), all four markers appeared to have comparable AUCs, ranging from 0.645 for SAA to 0.711 for sIL2R. CONCLUSION: sIL2R appears to be useful for monitoring respiratory disease severity in sarcoidosis. We recommend sIL2R measurement in the follow-up of patients with sarcoidosis.