Rapid point-of-care capillary hepatitis C virus (HCV) RNA quantification could remove barriers to chronic hepatitis C diagnosis and treatment.
To evaluate the diagnostic accuracy of rapid ...point-of-care HCV RNA quantification by Cepheid®'s GeneXpert® in 100 µl capillary whole blood using our laboratory-based standard quantitative HCV polymerase chain-reaction (PCR) test (Roche Cobas® Ampliprep/Taqman) with 650 µl venous EDTA plasma as the reference test.
In a prospective study conducted between November 2016 and May 2019 in the Infectious Diseases Outpatient Clinic of a Swiss tertiary care hospital, all adults with an indication for HCV RNA quantification (including HCV treatment monitoring) and written informed consent provided venous and capillary blood for parallel testing. Up to October 2018, we used the Xpert® HCV Viral Load (VL) test (105 min; developed for 1 ml plasma or serum), for which 1 ml Cepheid® buffer was added to 100 µl finger-stick capillary whole blood (~55% plasma). Thereafter, the Xpert® HCV Viral Load Finger-Stick (VL FS) test (60 min; specifically developed for 100 µl capillary whole blood) was evaluated.
(1) Xpert® HCV VL test. Among 194 paired samples from 88 patients, 99 (51.0%) were positive using Cobas® in venous plasma. Sensitivity and specificity of the Xpert® HCV VL test with 100µl capillary whole blood was 97.0% (96/99; 95% confidence interval CI 91.5-99.0%) and 94.7% (90/95; 95% CI 88.3-97.7%), respectively. The eight (4.1%) discordant results (three false negative, five false positive) were all under direct acting antiviral (DAA) treatment (week 1-4 or end of treatment), when HCV RNA was near the limit of quantification (highest HCV RNA value missed by Xpert® 68 IU/ml). Quantifiable results (n = 68) correlated well (R2 = 0.9165) irrespective of genotype, sex and HIV status. On average, Xpert® HCV VL test results were 1.32 (±0.34) log IU/ml lower, which corresponds to the ~18-fold smaller plasma volume used (~55 vs 1000µl). (2) Xpert® HCV VL FS test: Among 33 paired samples from 23 patients, 15 (45.5%) were positive using Cobas® in venous plasma. Sensitivity and specificity of the Xpert® HCV VL FS test with 100 µl capillary whole blood was 100% (15/15; 95% CI 79.6-100%) and 88.9% (16/18; 95% CI 67.2-96.9%), respectively. The two (6.1%) discordant results (both false positive) were under DAA treatment (week 3 and 4), when HCV RNA was near the limit of quantification. Quantifiable results (n = 14) correlated well (R2 = 0.9899). On average, Xpert® HCV VL FS test results were 0.10 (±0.17) log IU/ml lower.
Point-of-care HCV RNA quantification in capillary whole blood is a convenient, rapid and reliable method to diagnose active HCV infection, monitor treatment response and detect reinfection. For patients with difficult venous access after long-term intravenous drug use, capillary testing removes a crucial barrier to HCV treatment and reinfection monitoring. Same-day results might improve linkage to care.
For patients with difficult venous access after long-term intravenous drug use, rapid point-of-care hepatitis C virus (HCV) RNA quantification in capillary whole blood with the Xpert® HCV Viral Load ...Fingerstick (VL FS) test (60 minutes) is a convenient and reliable method for diagnosing chronic HCV infection, monitoring treatment and detecting reinfection. However, an expensive GeneXpert® system must be available on site. In decentralised settings with a low case-load, dried blood spot (DBS) testing might be an alternative.
Between December 2019 and January 2021, patients with an indication for HCV RNA quantification and informed consent provided 100 µl capillary whole blood each for on-site Xpert® HCV VL FS testing (reference) and DBS testing in the laboratory. For the latter, 100 µl blood, collected with an EDTA Minivette®, were transferred to a Whatman® 903 filter card. After drying for at least 1 hour, the DBS sample was packed into a sealable plastic bag with desiccant and sent to the central laboratory of our hospital, where it was stored at -20°C. For HCV RNA extraction, the whole DBS was cut out with an 18-mm puncher and transferred into 1.3 ml guanidinium thiocyanate-containing buffer (provided by Cepheid®). After mixing and incubating at room temperature for 2-3 hours, 1 ml supernatant was analysed with the Xpert® HCV VL test (105 minutes) (filter paper absorbs 0.3 ml).
Of 109 paired samples from 67 patients, 38 (34.9%) were positive with the Xpert® HCV VL FS test. Sensitivity and specificity of DBS testing were 89.5% (34/38; 95% confidence interval CI 75.9-95.8%) and 97.2% (69/71; 95% CI 90.3-99.2%), respectively. The six (5.5%) discordant results (four false negative, two false positive) all were observed in samples with HCV RNA detectable below the limit of quantification after 2-8 weeks of pan-genotypic direct-acting antiviral treatment or 5 weeks after acute hepatitis C in a patient clearing HCV spontaneously. Quantifiable results (n = 30; 16 genotype 1, 7 genotype 3, 4 genotype 4, 1 genotype 1a and 3a, 2 unknown; HCV RNA range: 2.74-6.66 log IU/ml) correlated well (R2 = 0.981). On average, uncorrected DBS test results were 1.30 ± 0.14 log IU/ml lower than Xpert® HCV VL FS test results (~42 μl instead of the expected 1000 μl plasma used). Storage of DBS samples at room temperature for 7 days before freezing reduced HCV RNA by 0.29 ± 0.12 log IU/ml.
HCV RNA can reliably be quantified with the Xpert® HCV VL test in capillary dried blood spot samples. Thus, access to capillary HCV RNA quantification for diagnosing chronic HCV infection, monitoring treatment and detecting reinfection can be extended to decentralised settings with a low case load.
Abstract Background hepatitis C infections are detected by anti-HCV screening tests. Reactive anti-HCV results give no information about the presence or absence of hepatitis C viruses, or of ...unspecific reactivity. To obtain information about the viral load, HCV RNA measurements, following a reactive anti-HCV result, are performed in well equipped and specialised laboratories. Anti-HCV immunoblots are the only means to exclude non specific reactivity. The measurement of HCV core antigen (HCV-Ag), as an alternative to HCV RNA, is discussed, as it can be analysed on the same instrument as anti-HCV. Objectives The detection limit of HCV-Ag is crucial to use it in lieu of HCV RNA, in regard of the different genotypes. A renewed algorithm is proposed to exclude unspecific reactivity of anti-HCV. Study designs Samples were tested on Architect i2000SR (Abbott) for anti-HCV and HCV-Ag. HCV RNA measurements were obtained by Cobas Ampliprep/Taqman (Roche) or m2000rt® (Abbott). Results and Conclusions Comparison between HCV-Ag and HCV RNA from 126 samples of 101 patients with chronic hepatitis C gave linear regression R2 0.89, slope 0.885 and intercept −2.258, which were independent of the genotypes. The detection limit of HCV-Ag was between 2.4 and 4.5 Log10 IU/mL. A renewed algorithm for confirmation of reactive anti-HCV results is proposed: active or resolved hepatitis C infections or false reactivity can be differentiated by sequenced reflex testing due to HCV-Ag, anti-HCV immunoblot and HCV RNA.
Background Discriminating Mycoplasma pneumoniae (MP) from Streptococcus pneumoniae (SP) and viral etiologies of community-acquired pneumonia (CAP) is challenging but has important implications ...regarding empiric antibiotic therapy. We investigated patient parameters upon hospital admission to predict MP infection. Methods All patients hospitalized in a tertiary care hospital between 2013 and 2017 for CAP with a confirmed etiology were analyzed using logistic regression analyses and area under the receiver operator characteristics (ROC) curves (AUC) for associations between demographic, clinical and laboratory features and the causative pathogen. Results We analyzed 568 patients with CAP, including 47 (8%) with MP; 152 (27%) with SP and 369 (65%) with influenza or other viruses. Comparing MP and SP by multivariate logistic regression analysis, younger age (odds ration OR 0.56 per 10 years, 95% CI 0.42-0.73), a lower neutrophil/lymphocyte ratio (OR 0.9, 0.82-0.99) and an elevated C-reactive protein/procalcitonin (CRP/PCT) ratio (OR 15.04 5.23-43.26 for a 400 mg/μg cut-off) independently predicted MP. With a ROC curve AUC of 0.91 (0.80 for the >400 mg/μg cutoff), the CRP/PCT ratio was the strongest predictor of MP vs. SP. The discriminatory value resulted from significantly lower PCT values (p < 0.001) for MP, while CRP was high in both groups (p = 0.057). Comparing MP and viral infections showed similar results with again the CRP/PCT ratio providing the best information (AUC 0.83; OR 5.55 for the >400 mg/μg cutoff, 2.26-13.64). Conclusions In patients hospitalized with CAP, a high admission CRP/PCT ratio predicts M. pneumoniae infection and may improve empiric management.
Abstract
Background
Hepatitis C virus (HCV) antigen testing is less expensive than quantitative reverse-transcription polymerase chain reaction but has lower sensitivity for very low viral load ...(VLVL; HCV RNA ≤3000 IU/mL). Currently the benefits of antigen testing for screening are discussed, but data on prevalence and outcomes of persons with VLVL are scarce.
Methods
We assessed prevalence and predictors of VLVL by logistic regression in treatment-naive participants in the Swiss Hepatitis C Cohort Study. We analyzed if the last viral load after VLVL was low, compared cirrhosis and mortality in persons with and without VLVL, and evaluated the number of samples with VLVL that were reactive by antigen testing.
Results
We included 2533 treatment-naive persons with available quantitative HCV RNA testing results. Overall, 133 persons (5.3%) had a VLVL. Age 18–40 years, female sex, and human immunodeficiency virus coinfection were associated with VLVL. Of 72 persons with a viral load available after VLVL, 14% had a VLVL and 17% had spontaneous viral clearance. The prevalence and incidence of cirrhosis and mortality were comparable in persons with and without VLVL; all 24 persons with VLVL and cirrhosis had excessive alcohol consumption or immunosuppression. Overall, 33% of samples with VLVL were reactive by antigen testing.
Conclusions
The frequency of VLVL was low. Among the persons who would probably be missed by antigen screening, some had a favorable disease course, but some had immunosuppression and liver cirrhosis. The benefit of HCV antigen testing for screening may be limited by the risk of missing patients with severe liver disease.
Among 2533 chronically hepatitis C–infected, treatment-naive persons in the Swiss Hepatitis C Cohort Study, 133 persons (5.3%) ever had a viral load ≤3000 IU/mL. Part of these showed favorable disease courses, but 24 persons, all immunosuppressed, had cirrhosis.
Nosocomial fungal infections are gaining increased attention from infectiologists. An adequate investigation into the levels of airborne Aspergillus and other fungal spores in hospital settings, ...under normal conditions, is largely unknown. We monitored airborne spore contamination in a Swiss hospital building in order to establish a seasonally-dependent base-line level. Air was sampled using an impaction technique, twice weekly, at six different locations over one year. Specimens were seeded in duplicate on Sabouraud agar plates. Grown colonies were identified to genus levels. The airborne Aspergillus spore concentration was constantly low throughout the whole year, at a median level of 2 spores/m³ (inter-quartile range = IQR 1-4), and displayed no seasonal dependency. The median concentration of other fungal spores was higher and showed a distinct seasonal variability with the ambient temperature change during the different seasons: 82 spores/m³ (IQR 26-126) in summer and 9 spores/m³ (IQR 6-15) in winter. The spore concentration varied considerably between the six sampling sites in the building (10 to 26 spores/m³). This variability may explain the variability of study results in the literature.
Urinary tract infections (UTIs) are common drivers of antibiotic use. The minimal effective duration of antibiotic therapy for UTIs is unknown, but any reduction is important to diminish selection ...pressure for antibiotic resistance, costs, and drug-related side-effects. The aim of this study was to investigate whether an algorithm based on procalcitonin (PCT) and quantitative pyuria reduces antibiotic exposure.
From April 2012 to March 2014, we conducted a factorial design randomized controlled open-label trial. Immunocompetent adults with community-acquired non-catheter-related UTI were enrolled in the emergency department of a tertiary-care 600-bed hospital in northwestern Switzerland. Clinical presentation was used to guide initiation and duration of antibiotic therapy according to current guidelines (control group) or with a PCT-pyuria-based algorithm (PCT-pyuria group). The primary endpoint was overall antibiotic exposure within 90 days. Secondary endpoints included duration of the initial antibiotic therapy, persistent infection 7 days after end of therapy and 30 days after enrollment, recurrence and rehospitalizations within 90 days.
Overall, 394 patients were screened, 228 met predefined exclusion criteria, 30 declined to participate, and 11 were not eligible. Of these, 125 (76% women) were enrolled in the intention-to-treat (ITT) analysis and 96 patients with microbiologically confirmed UTI constituted the per protocol group; 84 of 125 (67%) patients had a febrile UTI, 28 (22%) had bacteremia, 5 (4%) died, and 3 (2%) were lost to follow-up. Overall antibiotic exposure within 90 days was shorter in the PCT-pyuria group than in the control group (median 7.0 IQR, 5.0-14.0 vs. 10.0 IQR, 7.0-16.0 days, P = 0.011) in the ITT analysis. Mortality, rates of persistent infections, recurrences, and rehospitalizations were not different.
A PCT-pyuria-based algorithm reduced antibiotic exposure by 30% when compared to current guidelines without apparent negative effects on clinical outcomes.
This study assesses and demonstrates that CONTOUR® XT-BGMS (CXT-BGMS) complies with the requirements of the German (RiliBÄK) and Swiss (QUALAB) quality control guidelines for point-of-care testing ...(POCT) and fulfills the ISO15197:2013 accuracy limits criteria under the routine conditions of a hospital point-of care setting. This single-center study was conducted in Switzerland using 105 venous blood samples from hospitalized patients. Each sample was tested in comparison to the hexokinase reference method. Compliance with POCT guidelines was assessed by daily BGMS measurements using control solutions. Accuracy of CXT-BGMS according to ISO limits was 98.41%. All control measurements were within the limits defined by RiliBÄK (within ± 11% of target values and root mean square error RMSE within RMSE limits), and QUALAB (within ± 10% of target values).
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