Celiac Disease Diagnosis Without Biopsy: Is a 10× ULN Antitransglutaminase Result Suitable for a Chemiluminescence Method?

OBJECTIVES: 2012 European Society of Pediatric Gastroenterology, Hepatology and Nutrition guidelines allow to establish a celiac disease diagnosis without duodenal biopsy in symptomatic pediatric patients with antitissue transglutaminase (anti-tTG) titers >10 times the upper limit of normal. For some years now, new chemiluminescence immunoassays have been made available: it is important to establish the clinical performance of anti-tTG and to determine the cut-off best suited to predict Marsh ≥2 to avoid gastrointestinal endoscopy not only in children, but also in the adult population. METHODS: A total of 2565 patients performed duodenal biopsy from July 2012 to September 2016; we selected all the patients who had undergone QUANTA Flash anti-tTG immunoglobulin A (IgA) within -3 months of duodenal biopsy and before the start of gluten-free diet. A total of 827 patients fulfilled the criteria for selection. RESULTS: Using a cut-off of 20 chemiluminescent unit (CU; area under the curve: 0.995), sensitivity, specificity, positive, and negative predictive value were 98.2%, 98.4%, 97.9%, and 98.6%, respectively. For the correlation with Marsh ≥2, in the pediatric population, positive predictive values (PPV) were 92.1%, 99%, and 100% at 200 CU (10×), 560 CU (28×), and 1000 CU (50×), respectively. In the adult population PPV was 94.2%, 98.2%, and 100% at 200 CU (10×), 350 CU (15×), and 400 CU (20×). CONCLUSIONS: Sensitivity, specificity, positive, and negative predictive value of QUANTA Flash h-tTG IgA were excellent. The cut-off providing an optimized PPV for histological lesions compatible for celiac disease (Marsh ≥2) for the QUANTA Flash h-tTG IgA is 350 CU (15×) in adult and 560 CU (28×) in children.

Free light chains as a reliable biomarker of intrathecal synthesis in the diagnosis of CNS inflammatory diseases.

OBJECTIVE: To address the diagnostic performances of cerebrospinal fluid (CSF) free light chains (FLC) measurements compared to oligoclonal bands (OCB) to support multiple sclerosis (MS) diagnosis. RESULTS: kFLC index showed the highest diagnostic accuracy to detect MS patients with the highest AUC compared to OCB, IgG index, IF kFLC R, kFLC H, λFLC index and IF λFLC. CONCLUSIONS: FLC indices are biomarkers of intrathecal Immunoglobulin synthesis and central nervous system (CNS) inflammation. kFLC index can discriminate between MS and other CNS inflammatory disorders, while λFLC index is less informative for MS but can play a role to support the diagnosis of other inflammatory CNS disorders.

[PHYSICAL, CHEMICAL AND MORPHOLOGICAL URINE EXAMINATION: RECOMMENDATIONS FOR THE POST ANALYTICAL PHASE FROM THE INTERDISCIPLINARY URINALYSIS GROUP (GIAU)].

With these recommendations the Interdisciplinary Urinalysis Group (GIAU) aims to stimulate the following aspects : improvement and standardization of the post analytical approach to physical, chemical and morphological urine examination (ECMU); emphasize the value added to ECMU by selection of clinically significant parameters, indication of analytical methods, of units of measurement, of reference values; improvement of interpretation of dip stick urinalysis with particular regard to the reconsideration of the diagnostic significance of the evaluated parameters together with an increasing awareness of the limits of sensitivity and specificity of this analytical method. Accompanied by the skills to propose and carry out in-depth investigations with analytical methods that are more sensitive and specific;increase the awareness of the importance of professional skills in the field of urinary morphology and their relationships with the clinicians. through the introduction, in the report, of descriptive and interpretative comments depending on the type of request, the complexity of the laboratory, the competence of the pathologist;implement a policy of evaluation of the analytical quality by using, in addition to traditional internal and external controls, a program for the evaluation of morphological competence. The hope is to revalue the enormous potential diagnostic of ECMU, implementing a urinalysis on personalized diagnostic needs that each patient brings with it.

Performance evaluation of the new fully automated urine particle analyser UF-5000 compared to the reference method of the Fuchs-Rosenthal chamber.

BACKGROUND: UF-5000 is the new fully automated urine particle analyser. We validated its performance. METHODS: 736 urines were analysed and results were compared by two pathologists on uncentrifuged samples, using Fuchs-Rosenthal chamber. RESULTS: AUC of ROC curve ranged between 0.86 and 0.99. Sensitivity was >0.90 for all the elements and similar for RBC and yeasts. Specificity ranged between 0.74 and 0.89 for total cast, epithelial/non-squamous/renal-tubular cells and RBC. For all the other parameters specificity was >0.90. Comparison with Fuchs-Rosenthal chamber was very good for all the parameters; r ranged between 0.52 and 0.99 except for pathological cast because of the lack of the pathological samples in medium and higher ranges. Linearity performance (R2) was 1.00, 1.00 and 0.99 respectively for RBC, WBC and epithelial cells (EC). No carry-over was observed. The within-run imprecision was 25.42%,13.81%,1.36% for RBC; 37.50%,10.16%,1.41% for WBC and 35.25%, 17.85%,6.30% for EC at low, near the cut off level and high concentrations, respectively. The between-run imprecision was 6.90%,1.60% for RBC, 4.10%,1.90% for WBC and 7.60%,7.30% for EC, using low and high positive quality controls, respectively. CONCLUSION: UF-5000 is an analyser of great interest to detect urine particle related to pathological process of kidney and urinary tract.