Analytical evaluation and bioclinical validation of new aldosterone and renin immunoassays.

OBJECTIVES: Aldosterone and renin determinations play an important role in the etiological diagnosis of secondary hypertension. The analytical performances of new aldosterone and renin immunoassays on the Lumipulse G600II® system (Fujierbio) were investigated and compared with those of the iSYS® system (IDS) on patients concerned by medical investigations in a context of suspected or proven Primary aldosteronism. METHODS: By using the Lumipulse® G Aldosterone and Renin assays we performed imprecision study, linearity and method comparison (n=107). Accuracy of this new renin assay was tested using the International Standard (WHO IS 68/356). We also assessed the equivalence of the different samples types (n=29). RESULTS: The imprecision evaluation showed all CVs <3% and <6% for Lumipulse® G Aldosterone and Renin assays respectively. The linearity was excellent over the clinical range and the comparison with the iSYS® assays (n=79) showed a strong correlation (R2=1) despite a slight tendency to underestimation (bias of -17.53 pg/mL or 48.56 pmol/L for aldosterone and -15.395 pg/mL for renin). Moreover, the contingency studies based on diagnostic criteria showed that Lumipulse® G results lead to the same clinical diagnosis that iSYS® results. A clear correlation was obtained between EDTA and heparin plasma as well as with the serum for all range of measures. CONCLUSIONS: The Lumipulse® G Aldosterone and Renin assays present performances compatible with a routine use in medical laboratories. The precise quantification in the low range can be of interest in some clinical contexts especially standing/laying tests. However, the standardisation against the WHO International Standard Renin would be advisable.

Monitoring of ionized magnesium in hemodialysis patients: A useful tool to allow a personalized prescription of dialysate composition.

BACKGROUND AND AIMS: The dialysate magnesium (Mg) concentration is a major determinant of Mg balance in hemodialysis. This study aimed to assess the systemic variations of total (tMg) and ionized Mg (iMg) during a dialysis session using acetate or citrate fluids and 0.5 or 0.75 mM Mg. MATERIALS AND METHODS: 134 patients in maintenance hemodialysis were assigned to a dialysis session with 4 different dialysates: acetate fluid with 0.5 mM Mg (1) or 0.75 mM Mg (2), citrate fluid with 0.5 mM Mg (3) or 0.75 mM Mg (4). Ionized form was measured by direct ion-selective electrode. RESULTS: A Mg loss was observed in both acetate (0.12 and 0.08 mmol/L) and citrate (0.13 and 0.14 mmol/L for tMg and iMg, respectively) fluid groups containing 0.5 mM Mg. The use of acetate and citrate dialysates with 0.75 mM Mg led to a significant median intra-dialytic increase of 0.15 and 0.08 mmol/L for tMg, respectively. A significant augmentation in iMg concentration with acetate (0.11 mmol/L) but not with citrate dialysate (0.02 mmol/L) was observed. CONCLUSION: While a dialysate Mg concentration at 0.5 mM leads to a negative balance, increasing the concentration to 0.75 mM significantly raises post-dialysis circulating Mg. Monitoring of iMg should allow a personalized prescription in dialysate Mg.

Feedback on the Implementation of a Rapid and Connectable Point-of-Care COVID-19 Antigen Test in an Emergency Department.

Faced with the pandemic viral circulation of SARS-CoV-2, healthcare establishments have had to maintain an effective screening strategy in order to prevent nosocomial clusters. Automated antigenic tests appear to be a reliable and complementary alternative to RT-PCR (reverse transcriptase polymerase chain reaction) in order to optimize patient care in the emergency department. We report our experience of the deployment of the LumiraDx antigen tests on the LumiraDx platform, as well as the comparison of these tests' results with the RT-PCR results on a population of patients sampled in the emergency department.

Optimization of Patient Management in the Gynecology Emergency Department Using Point-of-Care Beta hCG.

Background: Point-of-care testing (POCT) provides shorter turn-around times and, in many cases, potentially improves medical decision making. The AQT90 FLEX® benchtop immunoanalyzer (Radiometer Medical ApS, Copenhagen, Denmark) allows for the determination of beta-human chorionic gonadotropin (ßhCG) in 18 min. The main aim of this study was to evaluate the impact of measuring ßhCG using the AQT90 analyzer in the gynecology emergency department (ED) compared to the standard practice of using central laboratory blood testing on the patient length of stay (LOS). Methods: The evaluation consisted of two parts. The first one, conducted in the central laboratory, focused on the analytical performances of the AQT ßhCG assay. The second one, conducted in the ED, aimed at determining the impact of POCT ßhCG implementation on the timeframe in which ED patients require ßhCG assessment. Results: The within-lab imprecisions at the mean values of 17 and 287 IU/L were 2.7% and 3.7%, respectively. Using Deming regression (n = 60), the following equation was obtained in the central lab: AQT90 ßhCG = 1.1 Roche ßhCG­12.9 (r = 0.997). The implementation of POCT ßhCG in the ED significantly reduced patient LOS (145 (90−212) min vs. 205 (155−265) with and without AQT90, respectively, p < 0.001). At the 2 IU/L decision level, a 99.7% agreement with the Roche assay was reported (kappa statistics, 0.99). Conclusions: We confirm that the analytical qualities of the AQT 90 were in line with those obtained in the central lab. The implementation of the POCT ßhCG is associated with a shorter LOS in the ED due to the faster availability of the results and the faster decision-making possibilities.