Development and validation of a commercial real-time NASBA assay for the rapid confirmation of influenza A H5N1 virus in clinical samples.

A real-time NASBA assay for the specific confirmation of influenza A H5N1 infection was developed and evaluated using proficiency panels distributed to the UK influenza network of laboratories and clinical samples received through the Chinese National Influenza Centre in Beijing. The aim of the proficiency panels was to determine the sensitivity and specificity of the assay on a range of influenza virus types and subtypes including different clades of influenza A H5 viruses. The assay was then evaluated using 19 clinical samples obtained from seven confirmed human cases of influenza A H5N1 infection in China.

Evaluation of the NucliSens Basic Kit assay for detection of Norwalk virus RNA in stool specimens.

Norwalk-like viruses (NLVs) are a genetically diverse group of human caliciviruses that are the most common cause of epidemic gastroenteritis and are detected typically in stool by reverse transcription (RT)-PCR or electron microscopy (EM). The application of a rapid nucleic acid sequence-based amplification (NASBA) assay for the detection of NLV RNA in stool is described using the NucliSens Basic Kit. Primers and probes for the NLV Basic Kit assay were based on the RNA polymerase region of the prototype NLV, Norwalk virus (NV) genome and could consistently detect 10(4) RT-PCR detectable units of NV RNA in a stool filtrate.

Characteristics and applications of nucleic acid sequence-based amplification (NASBA).

Nucleic acid sequence-based amplification (NASBA) is a sensitive, isothermal, transcription-based amplification system specifically designed for the detection of RNA targets. In some NASBA systems, DNA is also amplified though very inefficiently and only in the absence of the corresponding RNA target or in case of an excess (>1,000-fold) of target DNA over RNA. As NASBA is primer-dependent and amplicon detection is based on probe binding, primer and probe design rules are included.