Clinical Evaluation of Nasopharyngeal, Oropharyngeal, Nasal Swabs, and Saliva for the Detection of SARS-CoV-2 by Direct RT-PCR.

Nasopharyngeal swab (NPS) and oropharyngeal swab (OPS) are the most widely used upper respiratory tract specimens for diagnosis of SARS-CoV-2 using RT-qPCR. In contrast, nasal swab (NS) and saliva (SS), recently recommended by the WHO, are rarely used, and their test accuracy is limited. The method for direct RT-PCR detection of SARS-CoV-2 does not require an RNA extraction and is faster and easier than standard RT-PCR tests with RNA extraction.

Recombinant HBsAg of the Wild-Type and the G145R Escape Mutant, included in the New Multivalent Vaccine against Hepatitis B Virus, Dramatically Differ in their Effects on Leukocytes from Healthy Donors In Vitro.

Immune-escape hepatitis B virus (HBV) mutants play an important role in HBV spread. Recently, the multivalent vaccine Bubo-Unigep has been developed to protect against both wild-type HBV and the most significant G145R mutant. Here, we compared the effects of recombinant HBsAg antigens, wild-type and mutated at G145R, both included in the new vaccine, on activation of a human high-density culture of peripheral blood mononuclear cells (PBMC) in vitro.

Identification of Hotspot Mutations in the N Gene of SARS-CoV-2 in Russian Clinical Samples That May Affect the Detection by Reverse Transcription-PCR.

Sensitive and reliable diagnostic test systems based on real-time PCR are of great importance in the fight against the ongoing SARS-CoV-2 pandemic. The genetic variability of the SARS-CoV-2 virus leads to the accumulation of mutations, some of which may affect the sensitivity of modern PCR assays. The aim of this study was to search in Russian clinical samples for new mutations in SARS-CoV-2 gene that can affect the detection by RT-PCR.

Detection of S-HBsAg Mutations in Patients with Hematologic Malignancies.

Multiple studies of hepatitis B virus (HBV) genetic variability and its relationship with the disease pathogenesis are currently ongoing, stemming from growing evidence of the clinical significance of HBV mutations. It is becoming increasingly evident that patients with hematologic malignancies may be particularly prone to a higher frequency of such mutations. The present report is the first extensive study of the prevalence of escape mutations in S-HBsAg, performed using isolates from 59 patients from hospital hematology departments with diagnoses of leukemia (n = 32), lymphoma (n = 20), multiple myeloma (n = 3), and non-tumor blood diseases (n = 4).

Limits of diagnostic accuracy of anti-hepatitis C virus antibodies detection by ELISA and immunoblot assay.

When human sera samples are tested for anti-hepatitis C virus (HCV) antibodies using different ELISA kits as well as immunoblot assay kits discrepant results often occur. As a result the diagnostics of HCV infection in such sera remains unclear. The purpose of this investigation is to define the limits of HCV serodiagnostics.

Performance of ELISA HBsAg Test Kits with Use of the Different Types of Panels Containing HBsAg.

Serological diagnostics of hepatitis B in clinical laboratories is mainly based on detection of HBs antigen (HBsAg) in human serum or plasma using commercial ELISA kits. In manufacturing and laboratory practice, sensitivity of ELISA kit is measured against either international or national reference standard. This approach is necessary, but limited as it does not take into account factors that influence on HBsAg detection kit potency at low HBsAg concentration and when HBsAg subtypes/variants are present in species.