HCV RNA quantification in capillary dried blood spots with the Xpert® HCV Viral Load test for diagnosing chronic HCV infection, monitoring treatment and detecting reinfection.

BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSION: 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.

Very Low Hepatitis C Viral Loads in Treatment-naive Persons: Do They Compromise Hepatitis C Virus Antigen Testing?

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.

Rapid point-of-care HCV RNA quantification in capillary whole blood for diagnosing chronic HCV infection, monitoring treatment and detecting reinfection.

BACKGROUND: Rapid point-of-care capillary hepatitis C virus (HCV) RNA quantification could remove barriers to chronic hepatitis C diagnosis and treatment. AIMS: 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. METHODS: 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. RESULTS: (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. CONCLUSIONS: 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.

Validation of a Prediction Rule for Legionella Pneumonia in Emergency Department Patients.

We validated a clinical prediction rule for Legionella based on clinical parameters (dry cough, fever) and laboratory findings (C-reactive protein, lactate dehydrogenase, sodium, platelet counts) in 713 consecutive patients with community-acquired pneumonia. The Legionella Score performed well in estimating the likelihood for Legionella infection and thus may help to direct diagnostic and therapeutic decisions.

A high C-reactive protein/procalcitonin ratio predicts Mycoplasma pneumoniae infection.

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.

Performance of a Blood Glucose Monitoring System in a Point-of-Care Setting.

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).

Non-Seasonal Variation of Airborne Aspergillus Spore Concentration in a Hospital Building.

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.

Procalcitonin and pyuria-based algorithm reduces antibiotic use in urinary tract infections: a randomized controlled trial.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: A PCT-pyuria-based algorithm reduced antibiotic exposure by 30% when compared to current guidelines without apparent negative effects on clinical outcomes.

Detection limit of architect hepatitis C core antigen assay in correlation with HCV RNA, and renewed confirmation algorithm for reactive anti-HCV samples.

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 R(2) 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 Log(10)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.

Procalcitonin, pyuria and proadrenomedullin in the management of urinary tract infections--'triple p in uti': study protocol for a randomized controlled trial.

BACKGROUND: Urinary tract infections (UTIs) are among the most common infectious diseases and drivers of antibiotic use and in-hospital days. A reduction of antibiotic use potentially lowers the risk of antibiotic resistance. An early and adequate risk assessment combining medical, biopsychosocial and functional risk scores has the potential to optimize site-of-care decisions and thus allocation of limited health-care resources. The aim of this factorial design study is twofold: first, for Intervention A, it investigates antibiotic exposure of patients treated with a protocol based on the type of UTI, procalcitonin (PCT) and pyuria. Second, for Intervention B, it investigates the usefulness of the prognostic biomarker proadrenomedullin (ProADM) integrated into an interdisciplinary assessment bundle for site-of-care decisions. METHODS AND DESIGN: This randomized controlled open-label trial has a factorial design (2 × 2). Randomization of patients will be based on a pre-specified computer-generated randomization list and independent for the two interventions. Adults with UTI presenting to the emergency department (ED) will be screened and enrolled after providing informed consent. For our first Intervention (A), we developed a protocol based on previous observational research to recommend initiation and duration of antibiotic use based on the clinical presentation of UTI, pyuria and PCT levels. For our second intervention (B), an algorithm was developed to support site-of care decisions based on the prognostic marker ProADM and distinct nursing factors on days 1 and 3. Both interventions will be compared with a control group conforming to the guidelines. The primary endpoints for the two interventions will be: (A) overall exposure to antibiotics and (B) length of physician-led hospitalization within a follow-up of 30 days. Endpoints are assessed at discharge from hospital, and 30 and 90 days after admission. We plan to screen 300 patients and enroll 250 for an anticipated estimated loss of follow-up of 20%. This will provide adequate power for the two interventions. DISCUSSION: This trial investigates two strategies for improved individualized medical care in patients with UTI. The minimally effective duration of antibiotic therapy is not known for UTIs, which is important for reducing the selection pressure for antibiotic resistance, costs and drug-related side effects. Triage decisions must be improved to reflect the true medical, biopsychosocial and functional risks in order to allocate patients to the most appropriate care setting and reduce hospital-acquired disability. TRIAL REGISTRATION NUMBER: ISRCTN13663741.

[Improved sensitivity in detecting renal diseases by combined urinanalysis (proteins and cellular components)]. / Verbesserte Sensitivität bei Nieren- und Harnwegserkrankungen durch Kombination von Teststreifen, automatisiertem bzw. standardisiertem Urinsediment und differenzierter Proteinbestimmung im Urin.

New technologies and methods allow better diagnosis of renal and urinary tract diseases. On one hand the safe handling of renal biopsies and on the other hand the precise measurement of test strips and urinary sediment analysis obtained by automatic reading devices, flow cytometry (UF-100) or video imaging (Iris) and/or the cost effective cell chamber systems (KOVA), and the measurement of cystatin C in the serum and the differentiated protein analyses in urine, make possible earlier and better diagnoses. The exclusive analyses of the traditional urinary sediment and creatinin values are considered not being sufficient to exclude a renal disease. The follow-up with precise values allow for early intervention in case of failure of therapy (i.e. urinary tract infection) or deterioration of an underlying disease.

Time-course of quantitative urinary leukocytes and bacteria counts during antibiotic therapy in women with symptoms of urinary tract infection.

BACKGROUND: Urinary tract infections are generally diagnosed by test strips and microscopic semi-quantitative sediment analyses. However, results are uncertain because of lacking standardisation and limited sensitivity in low-count-bacteriuria. Flow cytometry UF-100 was used to analyse particles quantitatively in urine in women with urinary tract infections during the period of antibiotic therapy. The aim was to follow the courses of leukocytes and bacteria during infections and to gain information about the reasons for successful or unsuccessful outcomes. METHOD: Quantitative leukocytes and bacterial counts in urine of 16 symptomatic women were performed at presentation and each day during the antibiotic treatment by flow cytometry UF-100. RESULTS: Leukocytes in urine were between 30 and 15,000 (x10(6)/L) at presentation (cut-off 20x10(6)/L). Bacteria counts from flow cytometry were mainly 5x10(9)/L-100x10(9)/L (cut-off of 3x10(9)/L). The deepest decreases in cell counts were noted during the first 24 h after initiation of therapy and gained normal values at the end of treatment in successful outcomes. A slower or no decrease was noted in unsuccessful treatments. CONCLUSION: The precise leukocyte and bacteria counting by flow cytometry and their follow-up during urinary tract infections gave early information about outcomes of therapy.

Increased sensitivity in detecting renal impairments by quantitative measurement of marker protein excretion compared to detection of pathological particles in urine sediment analysis.

BACKGROUND: Positive test strip results, pathological particles in urine and the presence of proteinuria are common findings in nephropathies. A comparison between these methods and renal biopsies became available with the introduction of quantitative measurement of marker proteins (albumin, transferrin, IgG, alpha(1)-microglobulin, retinol binding protein, alpha(2)-macroglobulin, Bence Jones proteins) and standardised urine sediment analysis by flow cytometry or microscopy. METHODS: A total of 400 urine samples were examined using marker protein patterns, test strips and quantitative sediment analyses. RESULTS: Results from standardised urine sediment analyses were compared with the excretion of renal marker proteins. Increased erythrocyte and leukocyte counts in urine were observed in only 29% and 39% of the samples for which pathological protein excretion was found. The sensitivity in detecting pathological particles in urine sediment, such as casts and/or dysmorphic erythrocytes, was only 19%. Renal biopsies from 65 patients who were classified as pathological were compared with proteinuria and sediment analyses. Increased excretion of marker proteins was found in all cases, whereas only 41% of the cellular urine sediments showed pathological results. CONCLUSIONS: Quantitative measurement of marker proteins from both the glomerular and tubular sides should be used upfront as screening parameters for the early detection of renal disorders.

Quantitative urine particle analysis: integrative approach for the optimal combination of automation with UF-100 and microscopic review with KOVA cell chamber.

BACKGROUND: Automated systems have enabled the counting of particles in urine to be standardized. Their superiority over traditional sediment analysis has been well documented, but they have not gained wide acceptance. The reasons for this are that sediment analysis has been performed and interpreted for decades. Additionally, pathologic casts and other unknown particles still must be confirmed under the microscope. Furthermore, comparison between the methods has revealed outliers and thus decreased confidence in automation. METHODS: We used the standardized KOVA cell chamber system to count particles and compared the results with UF-100 flow cytometry as an alternative to traditional sediment analysis. RESULTS: We compared 252 randomly selected urine samples and obtained a review rate of 33%. Microscopic verification was necessary because of the presence of casts, yeast, sperm, dysmorphic erythrocytes, and some misclassified erythrocytes or leukocytes that were detected by incongruent dipstick results and abnormal scattergrams. We obtained correlation coefficients of 0.966 for erythrocytes and 0.935 for leukocytes. Criteria for an algorithm to identify samples that needed microscopic review were derived from comparisons between the number of particles from UF-100, dipstick results, cell chamber counting, and sediment analysis. CONCLUSIONS: Automated cell counting combined with microscopic counting with a standardized cell chamber system is useful. An objective algorithm for review criteria can be developed via systematic comparison of UF-100 flow cytometry and microscopy. Only urine samples that meet these criteria need to be confirmed microscopically.