Monoclonal gammapathy <5 g/L: the interest of T/O ratio.

There is currently no consensus for the quantification and identification of weak gammaglobulin monoclonal spike. We conducted a study of 12 months including 410 serum protein electrophoresis (SPE) with suspected weak monoclonal spike in gammaglobulin area without anteriority, which led to the realization of an immunofixation (IF); 276 SPE has a weak spike in gammaglobulins (defined with perpendicular drop method (orthogonal (O) quantification <5 g/L) but only 157 (57%) has monoclonal immunoglobulin by immunofixation of serum. The monitoring of 50 true positive monoclonal immunoglobulins showed the stability of the spike at more than half of the patients and its disappearance in 28% of cases. The number of true positives spike raise when using the tangent skimming method quantification (T) rather than the orthogonal method (O). The distribution of true positives based on T/O ratio propose a 6% threshold below which a monoclonal immunoglobulin is rarely found (VPNR>6%=73.7%), and a 10% threshold above more than 80% of true positives are detected (VPPR>10%=94.4%). The use of the T/O ratio could i) help to predict the presence of an IM when low intensity spike is detected, and help to choose between the realization of an immunofixation or a control of SPE later; ii) be a key tool for an inter-laboratory harmonization of IM follow up.

[Smartphone application for blood gas interpretation]. / Interprétation biologique des gaz du sang par une application pour smartphone.

Ninety four per cent of health professionals use their smartphone for business purposes and more than 50% has medical applications. The «Blood Gas¼ application was created to be part of this dynamic and participate to e-health development in France. The «Blood Gas¼ application facilitates interpretation of the results of blood gas analysis using an algorithm developed with reference to a medical bibliography. It can detect some complex or intricate acid-base disorders in evaluating the effectiveness of the secondary response. The application also studied the respiratory status of the patient by calculating the PaO2/FiO2 ratio and the alveol-arterial gradient. It also indicates the presence of a shunt effect. Finally, a specific module to calculate the SID (strong ion difference) depending on the model of Stewart can detect complex acid-base disorders.

Validation of a new standardized cystatin C turbidimetric assay: evaluation of the three novel CKD-EPI equations in hypertensive patients.

OBJECTIVES: Analytical and clinical performances of the new standardized cystatin C particle-enhanced turbidimetric immunoassay (PETIA) using DiaSys reagents on Olympus AU2700® analyzer were evaluated. DESIGN AND METHODS: We have studied imprecision, linearity, limit of detection and limit of quantification of this new immunoassay. Method comparison was assessed in relation to results generated by the standardized Siemens-particle-enhanced nephelometric immunoassay (PENIA). In order to evaluate the clinical relevance of this assay, estimated glomerular filtration rate (GFR) was calculated using MDRD, CKD-EPI creatinine, CKD-EPI cystatin C 2012 and CKD-EPI creatinine-cystatin C 2012 equations and compared to GFR measured using urinary clearance of (99m)Tc-DTPA in 100 hypertensive patients. RESULTS: Cystatin C measurements using DiaSys reagents have reliable analytical performances and are comparable to the standardized Siemens-PENIA method (bias of 0.01 mg/L). The mean measured GFR was 90.0±29.7 mL/min/1.73 m². Bias and accuracy of the three CKD-EPI equations were better than the MDRD. Both CKD-EPI creatinine-based and cystatin C-based formulae had similar bias, precision and accuracy. The combined creatinine-cystatin C equation was significantly more accurate and precise than the CKD-EPI creatinine equation in patients with GFR above 60 mL/min/1.73 m². CONCLUSIONS: The use of cystatin C in a combined equation with creatinine could improve the accuracy of eGFR in the reference interval.