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The Directigen™ EZ RSV test is a rapid chromatographic immunoassay for the direct and qualitative detection of Respiratory Syncytial Virus (RSV) antigen in nasopharyngeal washes, nasopharyngeal aspirates, nasopharyngeal swabs and nasopharyngeal swab/washes from patients suspected of having a viral respiratory infection. This test is intended for in vitro diagnostic use to aid in the diagnosis of Respiratory Syncytial Virus (RSV) infections in neonatal and pediatric patients under the age of 20. It is recommended that negative test results be confirmed by cell culture.

Viral respiratory tract infections are responsible for widespread disease. Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections in young children during the cold season.¹ RSV has also been implicated in severe respiratory infections in the elderly and immunocompromised.^2,3 More recently, RSV has been identified as causing 20% of "influenzalike" illness in people 15–44 years of age.⁴

Traditional methods for detection of respiratory viruses have included cell culture and direct fluorescent antibody (DFA).^5-7 More recently, PCR has shown clinical utility for the detection of respiratory viruses including RSV.⁸ Enzyme immunoassay (EIA) and rapid manual systems are available for specific viruses such as Influenza A/B and RSV. Rapid tests allow for a quick diagnosis so that patients may be appropriately isolated and treated to prevent the nosocomial spread of infections to fellow patients with compromised cardiac, respiratory or immune functions.⁹ In addition, rapid tests assist with the selection of appropriate antiviral therapy.

The most common specimens collected for RSV testing include nasopharyngeal washes, nasopharyngeal aspirates and nasopharyngeal swabs. Nasopharyngeal washes and aspirates have been shown to be superior to swabs and are the specimens of choice.¹⁰

The Directigen EZ RSV antigen detection test is a chromatographic assay to detect RSV antigens extracted from various specimens of symptomatic patients. The speed and workflow of the Directigen EZ RSV test make it applicable as a "STAT" RSV antigen detection test, providing rapid, relevant information to assist with antiviral intervention and other clinical or support decisions.

Quality control requirements must be performed in accordance with local, state and/or federal regulations or accreditation requirements and your laboratory's standard Quality Control procedures. It is recommended that the user refer to CLSI (formerly NCCLS) EP12-A¹⁷ and 42 CFR 493.1202 (c)¹⁸ for guidance on appropriate Quality Control practices.

Each BD RSV device contains built-in controls. Built-in control features include:

Internal Control: The appearance of a reddish-purple control line provides an internal antigen control (positive internal control) that serves as a reagent check for the conjugate and capture antibody as well as ensuring sufficient capillary flow has occurred. The absence of this line indicates an uninterpretable test.

Test Membrane Control (negative internal control): The unreactive membrane surface surrounding the positive internal control and test lines contrasts with a positive reaction and therefore serves as a background reference for interpreting reaction color.

The following are included in the Directigen EZ RSV kit.

For in vitro Diagnostic Use.

1. The RSV Control (+) Swab and the control line on the BD RSV device have been prepared from RSV-infected tissue culture cells which have been inactivated by detergent treatment and sonication then subsequently tested by bioassay procedures.

2. Do not use the kit if the Controls do not yield appropriate results.

3. Pathogenic microorganisms, including hepatitis viruses and Human Immunodeficiency Virus, may be present in clinical specimens. "Standard Precautions"^11-14 and institutional guidelines should be followed in handling all items contaminated with blood and other body fluids.

4. Do not use kit components beyond the expiration date.

5. Do NOT mix reagents from different kit lot numbers. Do not reuse the device.

6. Reagents contain sodium azide, which is harmful by inhalation, in contact with skin and if swallowed. Contact with acids liberates very toxic gas. If there is contact with skin, wash immediately with plenty of water. Sodium azide may react with lead and copper plumbing to form highly explosive metal azides. On disposal, flush with a large volume of water to prevent azide build-up.