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Objective: To compare the laboratory tests conducted in real-life settings for patients with anemia with the expected prescriptions derived from an optimal checkup. Methods: A panel of experts formulated an “optimal laboratory test assessment'' specific to each anemia profile. A retrospective analysis was done of the laboratory tests conducted according to the type of anemia (microcytic, normocytic or macrocytic). Using an algorithmic system, the laboratory tests performed in real-life practice were compared with the recommendations suggested in the “optimal laboratory test assessment” and with seemingly “unnecessary” laboratory tests. Results: In the analysis of the “optimal laboratory test assessment”, of the 1179 patients with microcytic anemia, 269 (22.8%) had had one of the three tests recommended by the expert system, and only 33 (2.8%) had all three tests. For normocytic anemia, 1054 of 2313 patients (45.6%) had one of the eleven recommended tests, and none had all eleven. Of the 384 patients with macrocytic anemia, 196 (51%) had one of the four recommended tests, and none had all four. In the analysis of “unnecessary laboratory tests'', one lab test was unnecessarily done in 727/3876 patients (18.8%), i.e. 339 of 1179 (28.8%) microcytic, 171 of 2313 (7.4%) normocytic, and 217 of 384 (56.5 %) macrocytic anemias. Conclusion: Laboratory investigations of anemia remain imperfect as more than half of the cases did not receive the expected tests. Analyzing other diagnostic domains, the authors are currently developing an artificial intelligence system to assist physicians in enhancing the efficiency of their laboratory test prescriptions.

BackgroundIdentifying a specific threshold level of SARS-CoV-2 antibodies that confers protection in immunocompromised patients has been very challenging. The aim was to assess the threshold of 264 binding antibody units (BAU)/ml using four different SARS-CoV-2 antibody assays (Abbott, Beckman, Roche, and Siemens) and to establish a new optimal threshold of protection for each of the four antibody assays.MethodsThis study was performed on data retrieved from 69 individuals, who received at least one dose of the Pfizer/BioNTech BNT162b2 or Moderna COVID-19 vaccine (Spikevax) at the Alphabio Laboratory in Marseille, France (European Hospital, Alphabio-Biogroup). The results were compared to the percent inhibition calculated using a functional surrogate of a standardized virus neutralization test (Genscript).ResultsSamples from 69 patients were analyzed. For a reference cutoff of 264 BAU/ml, assays showed moderate to good overall concordance with Genscript: 87% concordance for Abbott, 78% for Beckman, 75% for Roche, and 88% for Siemens. Overall concordance increased consistently after applying new thresholds, i.e., 148 BAU/ml (Abbott), 48 (Beckman), 559 (Roche), and 270 (Siemens).ConclusionWe suggest specific adjusted thresholds (BAU/ml) for the four commercial antibody assays that are used to assess pre-exposure prophylaxis in immunocompromised patients.

OBJECTIVES:. To determine the effect of the awake prone position (APP) on gas exchange and the work of breathing in spontaneously breathing patients with COVID-19–associated acute hypoxemic respiratory failure (AHRF) supported by high-flow nasal oxygen. DESIGN:. Prospective randomized physiologic crossover multicenter trial. SETTINGS:. Four ICUs in Marseille, France. PATIENTS:. Seventeen patients with laboratory-confirmed COVID-19 pneumonia and Pao2/Fio2 less than or equal to 300 mm Hg while treated with high-flow nasal cannula oxygen therapy. INTERVENTIONS:. Periods of APP and semirecumbent position (SRP) were randomly applied for 2 hours and separated by a 2-hour washout period. MEASUREMENTS AND MAIN RESULTS:. Arterial blood gases, end-tidal CO2. and esophageal pressure were recorded prior to and at the end of each period. Inspiratory muscle effort was assessed by measuring the esophageal pressure swing (∆PES) and the simplified esophageal pressure–time product (sPTPES). The other endpoints included physiologic dead space to tidal volume ratio (VD/VT) and the transpulmonary pressure swing. The APP increased the Pao2/Fio2 from 84 Torr (61–137 Torr) to 208 Torr (114–226 Torr) (p = 0.0007) and decreased both the VD/VT and the respiratory rate from 0.54 (0.47–0.57) to 0.49 (0.45–0.53) (p = 0.012) and from 26 breaths/min (21–30 breaths/min) to 21 breaths/min (19–22 breaths/min), respectively (p = 0.002). These variables remained unchanged during the SRP. The ∆PES and sPTPES per breath were unaffected by the position. However, the APP reduced the sPTPES per minute from 225 cm H2O.s.m–1 (176–332 cm H2O.s.m–1) to 174 cm H2O.s.m–1 (161–254 cm H2O.s.m–1) (p = 0.049). CONCLUSIONS:. In spontaneously breathing patients with COVID-19–associated AHRF supported by high-flow nasal oxygen, the APP improves oxygenation and reduces the physiologic dead space, respiratory rate, and work of breathing per minute.

OBJECTIVES:. To identify COVID-19-associated immunophenotyping patterns at hospital admission and to determine if some patterns could predict the need for mechanical ventilation (MV). DESIGN:. Prospective observational monocentric cohort study. SETTING:. A university-affiliated hospital in Marseille, France. PATIENTS:. Thirty patients presenting with laboratory-confirmed COVID-19 pneumonia were enrolled within the first 48 hours of hospital admission and compared with 18 healthy controls. INTERVENTIONS:. None. MEASUREMENTS AND MAIN RESULTS:. Whole-blood leukocytes were immunophenotyped with a rapid and simplified one-step flow cytometry method. Thirty-eight immune and five laboratory parameters were compared first between COVID-19 patients and controls and then between the COVID-19 patients who received or not MV during their stays. The variables that significantly discriminated MV from non-MV patients in univariate analysis were entered into a multiple stepwise logistic regression analysis. The COVID-19 patients were predominantly male (87%), aged 61 years (50–71 yr), and 93% received early corticosteroid therapy. Sixteen patients (53%) were managed with noninvasive respiratory support, and 14 (47%) required MV. Compared with controls, COVID-19 patients were characterized by an immune signature featuring: 1) decreased HLA-DR expression on monocytes; 2) reduced basophils, eosinophils, T-cells, NK cells, and nonclassical monocyte count; and 3) up regulation of CD169 on monocytes, CD64 on neutrophils, the adhesion/migration markers (CD62L and CD11b), and the checkpoint inhibitor CD274 on myeloid cells. Among the COVID-19 patients, those who received MV had lower level of CD4 and HLA-DR on monocytes, lower CD8+ T-cell count, and higher lactate dehydrogenase at hospital admission. In multivariate analysis, only CD4 on monocytes (p = 0.032) and CD8+ T-cell count (p = 0.026) were associated with MV requirement. The model combining these two variables provided an area under curve of 0.97 (95% CI, 0.83–0.99). CONCLUSIONS:. The association of low CD4 on monocytes and low CD8+ T-cell count at hospital admission was highly predictive of the need for MV in hospitalized patients with COVID-19 pneumonia.

BackgroundThe role of atrial fibrillation (AF) drivers located at the left atrium, superior vena cava, crista terminalis and coronary sinus (CS) is well established. While these regions are classically targeted during catheter ablation, the role of right atrial appendage (RAA) drivers has been incompletely investigated.ObjectiveTo determine the prevalence and electrophysiological characteristics of AF driver’s arising from the RAA.Materials and methodsWe conducted a retrospective analysis of clinical and procedural data of 317 consecutive patients who underwent an AF ablation procedure after bi-atrial mapping (multipolar catheter). We selected patients who presented with a per-procedural RAA firing (RAAF). RAAF was defined as the recording of a sustained RAA EGM with a cycle length shorter than 120 ms or 120 < RAAF CL ≤ 130 ms and ratio RAA CL/CS CL ≤ 0.75.ResultsRight atrial/atrium appendage firing was found in 22 patients. The prevalence was estimated at 7% (95% CI, 4–10). These patients were mostly men (72%), median age: 66 yo ± 8 without structural heart disease (77%). RAAFs were predominantly found in paroxysmal AF patients (63%, 32%, and 5% for paroxysmal, short standing and long-standing AF, respectively, p > 0.05). RAAF median cycle length was 117 ms ± 7 while CS cycle length was 180 ms ± 10 (p < 0.01).ConclusionIn 317 consecutive AF ablation patients (22 patients, 7%) the presence of a high-voltage short-cycle-length right atrial appendage driver (RAAF) may conclusively be associated with AF termination. This case series exemplifies the not-so-uncommon role of the RAA in the perpetuation of AF.

Background: MSM are at particular risk of STIs due to sexual behavior and substance use. HIV PrEP use may increase this risk. Design: Our aim was to comparatively assess incident STIs among different at-risk groups—PLWHIV, HIV-negative PrEP and no-PrEP users—seen at our center early after PrEP implementation. Methods: Clinical data were retrospectively collected on 636 MSM seen at the Infectious Diseases Department between September 2016 and October 2018. STI incidence rate was assessed among groups for the whole period, as well as separately for each year of the study. Results: Overall STI incidence rate ratio was higher in HIV-neg when compared to PLWHIV. In multivariate analysis, STI risk was significantly higher among HIV-neg no-PrEP users compared to PLWHIV, while not different between PLWHIV and PrEP users.STI incidence globally increased during the first 2 years after PrEP approval among PLWHIV and no-PrEP users, stated by odds ratio (OR = 1.77 [1.23–2.55], p = 0.0020 and OR = 2.29 [0.91–5.73], p = 0.0774 respectively) while it remained rather stable for HIV-neg PrEP users (OR = 1.19 [0.60–2.38], p = 0.6181). The HIV-neg no-PrEP group remained at higher risk of STI than PLWHIV and PrEP users during the two periods. Conclusion: These results suggest that a proactive approach of an efficient follow-up of MSM participants since PrEP approval may have prevented an increase of the incidence of STIs among PrEP users.

Background. Antireflux mucosectomy, a new endoscopic treatment for gastroesophageal reflux disease, consists of endoscopic mucosal resection at the esophagogastric junction. This study aim was to evaluate the medium-term efficacy of the antireflux mucosectomy technique for patients with severe gastroesophageal reflux disease symptoms (proton pump inhibitor treatment-dependent or proton pump inhibitor treatment-resistant gastroesophageal reflux disease). Methods. Between January 2017 and June 2018, 13 patients with severe gastroesophageal reflux disease without hiatal hernia, with positive pH reflux, were included in this monocentric prospective pilot study. The primary outcome was clinical success, defined by improvement evaluated by the Gastroesophageal Reflux Disease Health Related Quality of Life Questionnaire at 24 months. Secondary outcomes were technical success, decreased use of proton pump inhibitors, patient satisfaction, and adverse events. Results. Thirteen patients [females=8 (62%)], mean age 59 (range, 54-68), were included. The antireflux mucosectomy procedure had technical success in all patients. At 24 months, for 11 patients, gastroesophageal reflux disease symptoms were significantly improved, and mean gastroesophageal reflux disease score decreased from 33 (range, 26-42) to 3 (range, 0-7) (p=0.001). Ninety-one percent (n=10) of patients had a lower proton pump inhibitor intake at 24 months. One patient had 3 endoscopic balloon dilatations for EGJ stenosis, two patients had melena ten days after procedure, and seven patients had thoracic or abdominal pain. Patient’s satisfaction at 24 months was 81%. Conclusions. In patients with severe gastroesophageal reflux disease, despite occurrence of several short-term adverse events, antireflux mucosectomy seemed effective in improving gastroesophageal reflux disease symptoms at 24 months. This trial is registered with ClinicalTrials: NCT03357809.

"AIM: To study if one of the two molecules could lead to a lower number of follow up visits and intra-vitreous injection (IVI) with the same efficacy. METHODS: ELU (or “elected” in French) study is a retrospective study conducted in real life in patients presenting suboptimal response after ranibizumab IVI (phase 1) and secondary switched to aflibercept (phase 2). The number of follow up visits and IVI were compared in both phases. Visual acuity (VA) evolution and “switching” reasons were secondary analyzed. RESULTS: We retrospectively included data of 33 patients (38 eyes) with age-related macular degeneration (AMD; mean age: 77±7.7y). The number of monthly follow up visits [median (Q1; Q3)]: was significantly lower with aflibercept (phase 2), respectively 1.0 (0.81; 1.49) visits in phase 1, versus 0.79 (0.67; 0.86) visits in phase 2. The median number of monthly IVI also significantly decreased in phase 2, respectively 0.67 (0.55; 0.90) IVI in phase 1, versus 0.55 (0.45; 0.67) IVI in phase 2. The mean VA evolution (VA final-VA initial) was similar in both phases, (P>0.05). Whatever the reason for “switching” (loss of efficacy, tachyphylaxis, tolerance problems), there was no incidence on VA evolution over the time. CONCLUSION: Our results show that switching from ranibizumab to aflibercept in “suboptimal” patients significantly reduce the number of follow up visits and IVI, with a comparable efficacy. This decrease in visit number could improve patients’ quality of life and reduce surgical risk by reducing the number of injections."

Background & aimLiver fibrosis screening in primary care population is a major public health issue. The FIB-4 index is a simple non-invasive fibrosis test combining age, transaminases, platelets count, developed for the diagnosis of advanced fibrosis. The aim of our study was to evaluate the interest of liver fibrosis screening using systematic calculation of FIB-4 in routine blood analysis.MethodsBetween December 2018 and May 2019, we conducted a prospective screening of liver fibrosis in 134 158 patients during a medical check-up including routine blood analysis. Among these patients, 29 707 had transaminases and platelets counts available and benefited from an automatic calculation of FIB-4. Results were obtained from 21 French clinical laboratories in the Bouches du Rhône region.ResultsAmong the 29 707 patients, 2161 (7.3%) had a high risk of advanced fibrosis (FIB-4>2.67). Individual investigation of patients with FIB-4>2.67 allowed to screen 1268 (1268/2161: 58.7%) patients who were not managed for any liver disease.ConclusionsThis work demonstrates the interest of FIB-4 for the screening of liver fibrosis in primary care population. Although additional clinical validation study is required to determine the utility and applicability of Fib-4 to daily practice, our study strongly supports this easy-to-implement strategy using a simple Fib-4 measure resulting from the use of available routine test results.

Background & aimWe investigated the combination of rapid antigen detection (RAD) and RT-qPCR assays in a stepwise procedure to optimize the detection of COVID-19.MethodsFrom August 2020 to November 2020, 43,399 patients were screened in our laboratory for COVID-19 diagnostic by RT-qPCR using nasopharyngeal swab. Overall, 4,691 of the 43,399 were found to be positive, and 200 were retrieved for RAD testing allowing comparison of diagnostic accuracy between RAD and RT-qPCR. Cycle threshold (Ct) and time from symptoms onset (TSO) were included as covariates.ResultsThe overall sensitivity, specificity, PPV, NPV, LR-, and LR+ of RAD compared with RT-qPCR were 72% (95%CI 62%-81%), 99% (95% CI95%-100%), 99% (95%CI 93%-100%), and 78% (95%CI 70%-85%), 0.28 (95%CI 0.21-0.39), and 72 (95%CI 10-208) respectively. Sensitivity was higher for patients with Ct ≤ 25 regardless of TSO: TSO ≤ 4 days 92% (95%CI 75%-99%), TSO > 4 days 100% (95%CI 54%-100%), and asymptomatic 100% (95%CI 78-100%). Overall, combining RAD and RT-qPCR would allow reducing from only 4% the number of RT-qPCR needed.ConclusionsThis study highlights the risk of misdiagnosing COVID-19 in 28% of patients if RAD is used alone. A stepwise analysis that combines RAD and RT-qPCR would be an efficient screening procedure for COVID-19 detection and may facilitate the control of the outbreak.

Background & aim Screening for genital infection (GI) such as bacterial vaginosis (BV) and yeast infection, for sexually transmitted infection (STI), and for asymptomatic carriage of group B streptococcus (GBS) in pregnant women are common reason for medical appointments. The diagnosis and control of GIs, STIs, and GBS are major issues, for fertility and overall well-being of affected women. Conventional testing is performed using vaginal/cervical classical sampling (VCS); this procedure requires pelvic examination performed by health care professionals which raises concerns among women. Vaginal-self-sampling (VSS), as an alternative to VCS, might capture more women. The aim was first to show non-inferiority of VSS compared with VCS to screen for GIs, STIs, and GBS; second to determine the feasibility of VSS. Methods VSS and VCS from 1027 women were collected by health care professionals and simultaneously carried out on each patient. GIs, STIs, and GBS were systematically screened in both paired VSS and VCS samples. Non-inferiority of VSS compared with VCS was assessed using z statistic for binomial proportions. Results Prevalence of GIs were 39.7% using VSS and 38.1% using VCS (p = 0.0016). Prevalence of STIs was 8.5% (VSS) vs 8.1% (VCS) (p = 0.0087). Prevalence of GBS was 13.4% (VSS) and 11.5% (VCS) (p = 0.0001). Most participants (84%) recommended the use of VSS. Conclusions This study shows that VSS was not inferior to VCS for the detection of GIs, STIs, and GBS. This study provides evidence that VSS can be used as a universal specimen for detection of lower genital tract infections in women. Study identification number ID-RCB 2014-A01250-4.

Background & aimScreening for genital infection (GI) such as bacterial vaginosis (BV) and yeast infection, for sexually transmitted infection (STI), and for asymptomatic carriage of group B streptococcus (GBS) in pregnant women are common reason for medical appointments. The diagnosis and control of GIs, STIs, and GBS are major issues, for fertility and overall well-being of affected women. Conventional testing is performed using vaginal/cervical classical sampling (VCS); this procedure requires pelvic examination performed by health care professionals which raises concerns among women. Vaginal-self-sampling (VSS), as an alternative to VCS, might capture more women. The aim was first to show non-inferiority of VSS compared with VCS to screen for GIs, STIs, and GBS; second to determine the feasibility of VSS.MethodsVSS and VCS from 1027 women were collected by health care professionals and simultaneously carried out on each patient. GIs, STIs, and GBS were systematically screened in both paired VSS and VCS samples. Non-inferiority of VSS compared with VCS was assessed using z statistic for binomial proportions.ResultsPrevalence of GIs were 39.7% using VSS and 38.1% using VCS (p = 0.0016). Prevalence of STIs was 8.5% (VSS) vs 8.1% (VCS) (p = 0.0087). Prevalence of GBS was 13.4% (VSS) and 11.5% (VCS) (p = 0.0001). Most participants (84%) recommended the use of VSS.ConclusionsThis study shows that VSS was not inferior to VCS for the detection of GIs, STIs, and GBS. This study provides evidence that VSS can be used as a universal specimen for detection of lower genital tract infections in women.Study identification numberID-RCB 2014-A01250-4.

Rapid detection of abnormal biological values using point-of-care (POC) testing allows clinicians to promptly initiate therapy; however, there are concerns regarding the reliability of POC measurements. We investigated the agreement between the latest generation blood gas analyzer and central laboratory measurements of electrolytes, bicarbonate, hemoglobin, hematocrit, and glucose.314 paired samples were collected prospectively from 51 critically ill patients. All samples were drawn simultaneously in the morning from an arterial line. BD Vacutainer tubes were analyzed in the central laboratory using Beckman Coulter analyzers (AU 5800 and DxH 800). BD Preset 3 ml heparinized-syringes were analyzed immediately in the ICU using the POC Siemens RAPIDPoint 500 blood gas system. We used CLIA proficiency testing criteria to define acceptable analytical performance and interchangeability.Biases, limits of agreement (±1.96 SD) and coefficients of correlation were respectively: 1.3 (-2.2 to 4.8 mmol/L, r = 0.936) for sodium; 0.2 (-0.2 to 0.6 mmol/L, r = 0.944) for potassium; -0.9 (-3.7 to 2 mmol/L, r = 0.967) for chloride; 0.8 (-1.9 to 3.4 mmol/L, r = 0.968) for bicarbonate; -11 (-30 to 9 mg/dL, r = 0.972) for glucose; -0.8 (-1.4 to -0.2 g/dL, r = 0.985) for hemoglobin; and -1.1 (-2.9 to 0.7%, r = 0.981) for hematocrit. All differences were below CLIA cut-off values, except for hemoglobin.Compared to central Laboratory analyzers, the POC Siemens RAPIDPoint 500 blood gas system satisfied the CLIA criteria of interchangeability for all tested parameters, except for hemoglobin. These results are warranted for our own procedures and devices. Bearing these restrictions, we recommend clinicians to initiate an appropriate therapy based on POC testing without awaiting a control measurement.

We report the case of a 19-year-old woman who received a complete vaccine program by Gardasil. After one year, Greiner HPV test revealed HPV51 positivity. This case report highlights the limits of the vaccine, and the need to have a clinical follow up of patients despite the vaccination program.

Microbiotas play critical roles in human health, yet in most cases scientists lack standardized and reproducible methods from collection and preservation of samples, as well as the choice of omic analysis, up to the data processing. To date, stool sample preservation remains a source of technological bias in metagenomic sequencing, despite newly developed storage solutions. Here, we conducted a comparative study of 10 storage methods for human stool over a 14-day period of storage at fluctuating temperatures. We first compared the performance of each stabilizer with observed bacterial composition variation within the same specimen. Then, we identified the nature of the observed variations to determine which bacterial populations were more impacted by the stabilizer. We found that DNA stabilizers display various stabilizing efficacies and affect the recovered bacterial profiles thus highlighting that some solutions are more performant in preserving the true gut microbial community. Furthermore, our results showed that the bias associated with the stabilizers can be linked to the phenotypical traits of the bacterial populations present in the studied samples. Although newly developed storage solutions have improved our capacity to stabilize stool microbial content over time, they are nevertheless not devoid of biases hence requiring the implantation of standard operating procedures. Acknowledging the biases and limitations of the implemented method is key to better interpret and support true associated microbiome patterns that will then lead us towards personalized medicine, in which the microbiota profile could constitute a reliable tool for clinical practice.

Background aimsDried blood spots (DBS) on filter paper have been successfully used to diagnose and monitor several infectious diseases. The aim was to investigate the performance of DBS in hepatitis B virus (HBV) diagnosis using commercial tests in comparison to standard methods.MethodsPaired DBS and plasma samples were collected from 200 patients: 100 patients with HBsAg negative status and 100 patients with HBsAg positive status. In the latter patient, HBeAg reactivity was tested. Ten samples of anti-HBs were collected from people vaccinated against HBV. We also studied 50 patients with positive HBV DNA viral load in plasma and 10 HBV DNA negative patients. HBV genotypes and gene polymerase mutations were determined in 10 randomly selected HBV-infected patients. The DBS sample consisted of 50 µL of whole blood, i.e. a 12-mm paper card.ResultsThe sensitivity thresholds of HBsAg and anti-HBs antibody were 0.30 ± 0.08 IU/mL and 18.11 ± 6.05 IU/mL, respectively, for DBS with 98% sensitivity and 100% specificity. Sensitivity was 98% and specificity 100% for the detection of HBV DNA on a blotter, considering an HBV DNA threshold of 914.1 ± 157.8 IU/ml. Ten patients had an HBeAg positive status in plasma, all were detected positive using DBS. HBV genotyping and mutation detection were successfully performed on DBS, with full concordance between the 10 paired DBS and plasma samples.ConclusionThis study shows DBS is a reliable alternative to plasma specimens for quantifying and detecting HBsAg, anti-HBs, HBeAg and genotyping. DBS may increase the opportunities for HBV testing and treatment follow-up in hard-to-reach individuals.

BACKGROUND & AIMS:Point mutations in the coding region of the interleukin 28 gene (rs12979860) have recently been identified for predicting the outcome of treatment of hepatitis C virus infection. This polymorphism detection was based on whole blood DNA extraction. Alternatively, DNA for genetic diagnosis has been derived from buccal epithelial cells (BEC), dried blood spots (DBS), and genomic DNA from serum. The aim of the study was to investigate the reliability and accuracy of alternative routes of testing for single nucleotide polymorphism allele rs12979860CC. METHODS:Blood, plasma, and sera samples from 200 patients were extracted (400 µL). Buccal smears were tested using an FTA card. To simulate postal delay, we tested the influence of storage at ambient temperature on the different sources of DNA at five time points (baseline, 48 h, 6 days, 9 days, and 12 days). RESULTS:There was 100% concordance between blood, plasma, sera, and BEC, validating the use of DNA extracted from BEC collected on cytology brushes for genetic testing. Genetic variations in HPTR1 gene were detected using smear technique in blood smear (3620 copies) as well as in buccal smears (5870 copies). These results are similar to those for whole blood diluted at 1/10. A minimum of 0.04 µL, 4 µL, and 40 µL was necessary to obtain exploitable results respectively for whole blood, sera, and plasma. No significant variation between each time point was observed for the different sources of DNA. IL28B SNPs analysis at these different time points showed the same results using the four sources of DNA. CONCLUSION:We demonstrated that genomic DNA extraction from buccal cells, small amounts of serum, and dried blood spots is an alternative to DNA extracted from peripheral blood cells and is helpful in retrospective and prospective studies for multiple genetic markers, specifically in hard-to-reach individuals.

BackgroundThe risk of male-to-female intravaginal HIV-1 transmission is estimated at about 1 event per 200-2000 coital acts. The aim of this study was to assess the residual risk of HIV presence in semen in patients under HAART therapy.Methods and findingsThe study took place in France from October 2001 to March 2009. 394 paired blood and semen samples were provided from 332 HIV-1 infected men. The Roche Cobas AMPLICOR Monitor HIV assay was used to quantify HIV-1 RNA in blood and in seminal plasma. Three percent of 394 HIV-1 infected men enrolled in an assisted reproductive technology program harbored detectable HIV-1 RNA in semen, although they had no other sexually transmitted disease and their blood viral load was undetectable for at least 6 months under antiretroviral treatment.ConclusionThese data suggest that undetectable plasma HIV RNA means a lower risk of viral transmission through seminal fluid on a population level, but not necessarily at the level of the individual.