Summary
Introduction
Activated protein C resistance (APCr) leads to hypercoagulability and is due, often but not exclusively, to Factor V Leiden (FVL). The aim of this study was to assess the ex vivo ...and in vitro interference of the direct factor Xa inhibitor rivaroxaban (RIV) on a prothrombinase‐based assay for APCr detection.
Methods
An ex vivo study was performed on fresh plasma samples obtained from 44 subjects with FV wild‐type and seven with FVL heterozygous, all treated with RIV. An in vitro study was performed on 15 plasma samples (six from normal subjects, six from heterozygous, and three from homozygous FVL carriers, all frozen specimens) spiked with RIV. RIV concentration was evaluated using a chromogenic assay, and APCr was evaluated by a prothrombinase‐based assay.
Results
No significant interference of RIV on APCr results obtained by a prothrombinase‐based assay was observed for drug concentrations up to 400 ng/mL in FV wild‐type and FVL carriers (homozygous and heterozygous). These results were confirmed both ex vivo and in vitro.
Conclusions
RIV did not significantly interfere with the prothrombinase‐based assay used for the assessment of APCr, and this was observed to occur independently of FV status. However, only concentrations up to 400 ng/mL were tested and, therefore, what occurs in the presence of higher doses remains to be investigated.
Abstract Because urinary tract infections (UTIs) are a quite common disease, the gold standard for diagnosing UTIs is still bacterial culture, although a large percentage of samples are negative: ...unnecessary cultures can be reduced by means of an effective screening test. The analytic performance of a new urine cytometer, the UF-1000i, has been tested on 1463 urine samples submitted to our laboratory for culture. Bacteria and leukocyte counts have been compared by means of the UF-1000i with colony-forming unit (CFU) quantification on citrate lactose electrolytes deficient agar to assess the best cutoff values. By using quantitative cultures and considering as positive a sample with 10 × 105 CFU/mL, 546 positive samples (37%) were observed. If compared with 10 × 105 CFU/mL, the cutoff values obtained were 125 bacteria/μL and 40 leukocytes/ μL, respectively. Analytic parameters such as sensitivity, specificity, positive predictive value, negative predictive value, and correctly classified incidence were satisfactory. Based on the results obtained in this study, when using the UF-1000i analyzer for a screening test for UTI, a cutoff value of 40 white blood cells/μL should be adopted. The cutoff value for bacteria should be 125/μL for those clinical conditions in which 10 × 105 CFU/mL indicates a positivity.
In this study, we evaluated the GeneXpert HemosIL Factor II and Factor V assay, an innovative assay for the detection of Factor V Leiden (FVL) and prothrombin G20210A mutation (GPRO).
We evaluated ...132 patients that were previously classified (with a concordant result) using two commercial real-time PCR assays supplied, by Applied Biosystems and Roche Molecular Biochemicals. The cohort comprised 75 normal subjects, 10 FVL homozygous, 35 FVL heterozygous, 7 GPRO heterozygous, 2 GPRO homozygous and 3 double heterozygous FVL and GPRO subjects. All of the samples were evaluated using the GeneXpert HemosIL Factor II and Factor V assay.
All of the samples were correctly identified using the GeneXpert HemosIL Factor II and Factor V assay; therefore, in this patient series, the specificity and sensitivity of the test under evaluation was 1.00.
We have shown that the GeneXpert HemosIL Factor II and Factor V assay, a rapid fully automated assay, can accurately characterise the presence of FV G1691A and FII G20210A polymorphisms with specificity and sensitivity that are comparable to other current real-time PCR-based methods. The theoretical advantages of such an assay include improved standardisation across varying healthcare environments, more thorough sample manipulation and reduced human error.
► Factor V Leiden (FVL) and Prothrombin 20210 (GPRO) variant are well recognized thrombosis risk factors. ► In Chioggia we described a high prevalence of FVL and GPRO. ► We compared, in 132 previously classified samples, GeneXpert with two PCR based commercial methods. ► We observed a 100% concordance in samples classification. ►At our knowledge this is the first validation study performed by using GeneXpert analyzer in this application.
Aims The authors evaluated the analytical performance of the Sysmex UF-100 cytometer vs. the diagnosis of urinary tract infections (UTI).
Methods We considered 2010 subjects, aged between 18 and 78, ...870 males and 1140 females. The majority (90.2%) of the samples were voided urine specimens collected by using the midstream technique. Each sample was subjected to microbiological evaluation (culture + residual antibacterial activity), dipstick tests, UF-100 examination and microscopic observation. In order to obtain a final diagnosis of UTI these laboratory results were taken into consideration together with clinical data and patients' characteristics. The analytical performance of the laboratory tests was obtained by adopting this diagnosis as standard practice.
Results Out of the total 2010 subjects considered a clinical diagnosis of UTI was obtained in 529 cases (26.32%). The UF-100-based screening had sensitivity, 0.94; specificity, 0.93; positive predictive value, 0.83; negative predictive value, 0.98; and correctly classified incidence, 0.93.
Conclusions In our experience the results of the UF-100-based screening show a very good correlation with the diagnosis of acute UTI in adults patients.
Developed western countries are considered to be relatively free from endemic foci of hepatitis E virus (HEV) infections. The aim of this study was to assess the seroepidemiology of HEV in north-east ...Italy. Of the 2361 individuals studied 1889 were representative of the general population and 472 were from groups at high risk for viral infections: 279 drug users and 193 patients on chronic haemodialysis. All sera were tested for hepatitis C virus antibody (HCVAb), human immunodeficiency virus antibody (HIVAb) and for hepatitis B virus (HBV) serology. Two solid-phase enzyme-linked immunosorbent assays (ELISA) were used to study the seroepidemiology of HEV IgG, the first (using recombinant antigens) for confirmation of initially reactive samples. The prevalence of circulating hepatitis E virus antibody (HEVAb) was 2.6% in the open population, 5.4% among drug users and 9.3% among patients on chronic haemodialysis. In the open population a positive relationship between age and prevalence of HEVAb was observed. A relationship between presence of HEVAb and serological evidence of previous HBV or HCV infections was also observed in this study. It was concluded that HEV infections are present in north-east Italy and are more frequent among subjects at risk for blood-borne viral infections. The positive correlation, observed in the open population, between age and prevalence of HEVAb suggests the presence of a cohort effect.
In order to study the behaviour of traditional and new platelet parameters determined by the ADVIA 120 Hematology System, five hundred samples from reference subjects, divided for sex and age, were ...processed. Significant variations on the basis of sex and age were found. Reference ranges as 95% confidence limits were therefore calculated for each age class, and platelet parameters proved to have specific variations during lifetime. Moreover, one hundred samples from thrombocytopenic patients were processed by the ADVIA 120 System. When compared with those of reference subjects matched for sex and age, all platelet parameters, except mean platelet component (MPC), showed significant differences.
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