Design, validation and implementation of an automated e-alert for acute kidney injury: 6-month pilot study shows increased awareness.

BACKGROUND: Acute kidney injury (AKI) is defined as a sudden episode of kidney failure but is known to be under-recognized by healthcare professionals. The Kidney Disease Improving Global Outcome (KDIGO) guidelines have formulated criteria to facilitate AKI diagnosis by comparing changes in plasma creatinine measurements (PCr). To improve AKI awareness, we implemented these criteria as an electronic alert (e-alert), in our electronic health record (EHR) system. METHODS: For every new PCr measurement measured in the University Medical Center Utrecht that triggered the e-alert, we provided the physician with actionable insights in the form of a memo, to improve or stabilize kidney function. Since e-alerts qualify for software as a medical device (SaMD), we designed, implemented and validated the e-alert according to the European Union In Vitro Diagnostic Regulation (IVDR). RESULTS: We evaluated the impact of the e-alert using pilot data six months before and after implementation. 2,053 e-alerts of 866 patients were triggered in the before implementation, and 1,970 e-alerts of 853 patients were triggered after implementation. We found improvements in AKI awareness as measured by (1) 2 days PCr follow up (56.6-65.8%, p-value: 0.003), and (2) stop of nephrotoxic medication within 7 days of the e-alert (59.2-63.2%, p-value: 0.002). CONCLUSION: Here, we describe the design and implementation of the e-alert in line with the IVDR, leveraging a multi-disciplinary team consisting of physicians, clinical chemists, data managers and data scientists, and share our firsts results that indicate an improved awareness among treating physicians.

Stability and comparison of complete blood count parameters between capillary and venous blood samples.

INTRODUCTION: This study assessed the comparability of complete blood count (CBC) parameters between capillary and venous samples, and extended previous research by examining the influence of different storage temperatures on CBC stability up to 7 days after sample collection. METHODS: Venous and capillary blood samples were collected from 93 adult patients. Hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), mean platelet volume (MPV), leukocytes, lymphocytes, basophils, eosinophils, erythrocytes, red cell distribution width (RDW), immature granulocytes (IG), immature reticulocyte fraction (IRF), monocytes, neutrophils, platelets, and reticulocytes were measured. Deming regression and mean relative differences between venous and capillary measurements were contrasted with desirable total allowable error (TEa). Stability was assessed in 20-27 venous blood samples stored at 4, 21-22, or 30°C, and analyzed at 0, 24, 48, 72, 96, 120, 144, and 168 h. Mean relative change with respect to baseline measurements was compared to the desirable TEa to determine acceptable stability. RESULTS: Deming regression demonstrated strong linear correlations and acceptable variation between venous and capillary measurements. Erythrocytes, Hb, Ht, MCH, MCV, RDW, reticulocytes, and platelets showed acceptable stability for at least 96 h at 4°C. Mean relative change exceeded desirable TEa after 24 h at 30°C for all parameters, except erythrocytes, Hb, leukocytes, and MCH. CONCLUSION: Clinical laboratory specialists and clinicians should be aware of potential differences between venous and capillary measurements, and the influence of storage conditions. Clinical validity of delayed CBC analysis depends on the clinical situation and required precision of the result.

Analysis of C-reactive protein from finger stick dried blood spot to predict high risk of cardiovascular disease.

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 R2 (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.

A Preliminary Analysis of Thyrotropin Measurement from Finger Stick Dried Blood Spot with an Automated High-Throughput Immunoassay Analyzer.

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 R2 [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.

Comparison of capillary and venous blood sampling for routine coagulation assays.

OBJECTIVES: Capillary blood samples are generally assumed as unsuitable for coagulation testing since it is recognized that contamination with tissue factor and dilution with tissue fluid affects the coagulation assay. However, limited data is available about coagulations assays in which capillary blood sampling is compared to the standard venous blood withdrawal method. The aim of this study was to perform a method comparison between capillary and venous blood sampling for routine coagulation assays. METHODS: Both venous and capillary (finger stick) blood samples were collected from 188 healthy volunteers and patients. In citrate plasma, International Normalized Ratio (INR), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen, and D-dimer were measured according to routine protocols using the ACL-TOP 750 LAS (Werfen) coagulation analyzer. Regression analysis was performed and the mean relative difference between capillary and venous sampling was reflected to the total allowable error (TEa). RESULTS: Strong correlations and acceptable variations, using the TEa as decision limit, were found for INR, PT, TT, fibrinogen, and D-dimer between capillary and venous sampling. However, capillary sampling resulted in significant shorter APTT values when using the standard APTT-SP Liquid reagent with a mean bias of -10.4% [95% CI -12.4 to -8.4]. CONCLUSION: Based on these results, capillary blood sampling proved to be an alternative blood withdrawal method for routine coagulation assays, with the exception of APTT, if a venipuncture is unavailable or undesired.

EGF increases TRPM6 activity and surface expression.

Recent identification of a mutation in the EGF gene that causes isolated recessive hypomagnesemia led to the finding that EGF increases the activity of the epithelial magnesium (Mg2+) channel transient receptor potential M6 (TRPM6). To investigate the molecular mechanism mediating this effect, we performed whole-cell patch-clamp recordings of TRPM6 expressed in human embryonic kidney 293 (HEK293) cells. Stimulation of the EGF receptor increased current through TRPM6 but not TRPM7. The carboxy-terminal alpha-kinase domain of TRPM6 did not participate in the EGF receptor-mediated increase in channel activity. This activation relied on both the Src family of tyrosine kinases and the downstream effector Rac1. Activation of Rac1 increased the mobility of TRPM6, assessed by fluorescence recovery after photobleaching, and a constitutively active mutant of Rac1 mimicked the stimulatory effect of EGF on TRPM6 mobility and activity. Ultimately, TRPM6 activation resulted from increased cell surface abundance. In contrast, dominant negative Rac1 decreased TRPM6 mobility, abrogated current development, and prevented the EGF-mediated increase in channel activity. In summary, EGF-mediated stimulation of TRPM6 occurs via signaling through Src kinases and Rac1, thereby redistributing endomembrane TRPM6 to the plasma membrane. These results describe a regulatory mechanism for transepithelial Mg2+ transport and consequently whole-body Mg2+ homeostasis.