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Background: Hyper- and hypothyroidism are prevalent in Western countries and often go unnoticed for long periods. Thyrotropin (TSH) as a biomarker of thyroid dysfunction is regularly measured in venous plasma/serum. In newborn screening for congenital hypothyroidism, TSH is measured from dried blood spots (DBSs). DBS enables minimally invasive (at-home) sampling of a small blood volume that can be sent to diagnostic laboratories by regular mail. Methods: In this study, we included 109 patients who presented to the outpatient clinic of the University Medical Center Utrecht. Capillary finger stick was used to spot blood on a filter paper card and was dried. After extraction of TSH from DBS, method comparison with venous TSH was performed on an automated high-throughput immunoassay analyzer. Additional validation steps regarding stability, effect of hematocrit (Hct), precision, and limits of blank and quantitation were conducted according to corresponding Clinical and Laboratory Standards Institute evaluation protocol. Results: Method comparison of TSH from venous plasma versus finger stick DBSs showed an R 2 [95% confidence interval] = 0.988 [0.986-0.990]. This enabled correct diagnosis of hypothyrotropinemia and hypothyroidism in 12 of 14 and 6 of 7 cases, respectively, with no false positives. Furthermore, TSH from DBS was stable for at least 4 days at temperatures between -20°C and +30°C, and the maximum decrease of eluate TSH was 1.13% for 1% increase in Hct. Conclusions: TSH from DBS may be accurately measured on an automated high-throughput immunoassay analyzer and could be used to diagnose hypothyroidism and, for the first time, hypothyrotropinemia. This method, when confirmed in larger field studies, may enable individuals to engage in (at-home) sampling of blood on DBSs for telediagnostics, screening programs, patient follow-up, and medication management.

C-reactive protein (CRP) is an acute-phase protein involved in inflammation. Furthermore, CRP is an important biomarker used in diagnostics to predict risk of cardiovascular disease (CVD) in addition to monitoring bacterial and viral infections. To measure plasma CRP, venipuncture is still necessitated and has to be performed by trained phlebotomists. As a solution, dried blood spots (DBS) are used for minimally invasive at-home sampling of blood and can be send to diagnostic laboratories by regular mail. In this study, we included 53 patients that presented to the outpatient clinic of the University Medical Center Utrecht. Capillary finger stick was used to spot blood on a filter paper card and allowed to dry. After extraction of DBS, CRP was analyzed on an automated high-throughput chemistry analyzer. Additional validation steps regarding stability, effect of hematocrit, precision, and limits of blank and quantitation were conducted according to corresponding Clinical and Laboratory Standards Institute standards. An excellent regression analysis of R 2 (95% confidence interval) = 0.986 (0.982-0.989) was found. This enabled correct classification for high CVD risk of all 25 cases with sensitivity (95% CI) of 1.00 (1.00-1.00) and specificity (95% CI) of 0.96 (0.89-1.03) and correct diagnosis of inflammation of 12/13 cases with sensitivity (95% CI) of 0.92 (0.77-1.07) and specificity (95% CI) of 1.00 (1.00-1.00). Furthermore, CRP was found to be stable for 31 days and observed hematocrit variation amongst patients was clinically acceptable. CRP from DBS can be accurately measured on an automated high-throughput chemistry analyzer and used to diagnose inflammation and classify high CVD risk. This method enables individuals to engage in at-home sampling of blood on DBS for (tele)diagnostics, screening programs, patient follow-up, and medication management., (© 2023. The Author(s).)

Aim: To explore the influence of apical periodontitis (AP) on inflammatory markers in blood of otherwise healthy individuals and to depict the inflammatory profile of the healing after dental extraction., Methodology: This is a prospective case-control intervention study, during which, individuals with a diagnosis of AP of one affected tooth were included, along with a control group matched for age and gender. A broad panel of blood inflammatory mediators was examined longitudinally in all subjects during six visits. In the case of the AP subjects, the tooth with AP was extracted at the third visit. Results were analysed by linear regression analyses and linear mixed-model analyses., Results: A total of 53 subjects were included in the study, 27 with AP and 26 without. Fifteen females and 12 males were included in the AP group, and 14 females and 12 males in the control group. At baseline, granulocyte colony-stimulating factor (p < .001), interleukin (IL)-1β (p = .03) and IL-4 (p = .01) were significantly lower in AP subjects than in controls. Comparison of the differences between baseline and the last visit, i.e. 3 months after the tooth extraction, showed a significant reduction in IL-10 (p = .03) and IL-12p70 (p = .01)., Conclusions: The immunologic profile of chronic AP in one tooth and its healing profile reveals a systemic low-grade inflammation through compensatory immunosuppression. A larger lesion or multiple lesions could disrupt the balance that the system is trying to maintain, resulting in loss of homeostasis., (© 2022 The Authors. International Endodontic Journal published by John Wiley & Sons Ltd on behalf of British Endodontic Society.)