Viral Culture, Respiratory
Diagnosing viral infections in respiratory specimens
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
All routine viral cultures are inoculated into cell culture tubes for viral detection. The most common specimens received for routine testing include bronchoalveolar lavage, sputum, and throat. A rapid (16-hour incubation) shell vial cell culture assay will be inoculated when specimens are designated for herpes simplex virus or cytomegalovirus detection or as appropriate for source indicated.
If enterovirus or hand, foot, and mouth disease is suspected, clearly indicate "enterovirus" on request.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Viruses are responsible for a broad spectrum of clinical symptoms and diseases. The most commonly isolated viruses are adenovirus, cytomegalovirus (CMV), enteroviruses, herpes simplex virus (HSV), influenza virus, parainfluenza virus (types 1-3), respiratory syncytial virus (RSV), and varicella-zoster virus (VZV).
Many viral infections can now be treated with antiviral drugs. Early laboratory diagnosis by isolation is very helpful in the medical management of these patients.
Viruses that are detected in cell culture: adenovirus, CMV, enterovirus, HSV, VZV, RSV, influenza virus, and parainfluenza virus.
Viruses that are not detected in cell culture: Epstein-Barr virus, rubella virus (must order serology), and human papillomavirus, Norwalk or norovirus.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
If positive, virus is identified.
A positive result indicates that virus was present in the specimen submitted. Clinical correlation is necessary to determine the significance of this finding.
Influenza virus infection is a state-mandated reportable disease.
Negative results may be seen in a number of situations including absence of viral disease, inability of the virus to grow in culture (examples of organisms not detected by culture include Epstein-Barr virus, rubella virus, and papilloma virus), and nonviable organisms submitted. Parainfluenza virus type 4 also may not be detected by viral culture.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Viral isolation depends on the proper collection and transport of the specimen for maximal detection of viruses in the laboratory.
Some viruses (eg, cytomegalovirus) take up to 2 weeks to grow in viral cell culture. Molecular tests (ie, real-time PCR) should be used for rapid diagnosis.
This test is not useful for viruses that cannot be grown in cell culture (see Interpretation).
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Clinical and Laboratory Standards Institute 2005. Viral Culture. Proposed Guideline. CLSI document M41-P. Clinical and Laboratory Standards Institute, Wayne, PA
2. Ginocchio CC, Harris PC: Chapter 17: Reagents, stains, and cell culture: virology. In Manual of Clinical Microbiology. 10th edition. Edited by J Versalovic, KC Carroll, et al. Washington, DC, ASM Press, 2011, pp 1289-1296
3. Smith TF: Antibody-enhanced detection of viruses in cell cultures. In Manual of Clinical Laboratory Immunology. Fifth edition. Edited by NR Rose, EC de Marcio, JD Folds, et al. Washington, DC, ASM Press, 1997, pp 618-624