Is PCR Useful in the Diagnosis of Common Respiratory Viral Illnesses?

Summary and Comment |
March 17, 2014

Is PCR Useful in the Diagnosis of Common Respiratory Viral Illnesses?

  1. Deborah Lehman, MD

Polymerase chain reaction for some viruses can be positive in children with no symptoms.

  1. Deborah Lehman, MD

Detection of respiratory viruses by real-time polymerase chain reaction (PCR) in children with acute respiratory infection has led to shorter hospital stays, fewer courses of antibiotics, and better understanding of etiology. Benefits of viral detection are best described for influenza and respiratory syncytial virus (RSV), but the clinical significance is less certain of other viruses detected on PCR in both inpatient and outpatient settings. In a case-control study conducted at an emergency department in Sweden, investigators compared PCR results collected during a noninfluenza period in 209 children (age, ≤5 years) with acute respiratory symptoms and 209 age-matched asymptomatic controls receiving well-child care. Nasopharyngeal sampling was obtained from all children and tested by quantitative PCR for 16 viruses.

At least one respiratory virus was detected in 72% of cases and 35% of controls. Parainfluenza, RSV, and human metapneumovirus were primarily detected in cases. Human bocavirus and rhinovirus were detected in both cases (16% and 48%, respectively) and controls (4% and 22%, respectively), and human coronavirus and enterovirus (HEV) were detected with equal frequency in cases and controls. Twenty percent of cases and 5% of controls had more than one virus isolated. Coinfected cases had more severe disease.


Polymerase chain reaction testing is becoming widely available, allowing identification of viruses in acute respiratory infections. However, all viruses are not created equal. In this study, detection of parainfluenza, respiratory syncytial virus, and human metapneumovirus correlated with symptomatic infection. In contrast, human bocavirus, rhinovirus, coronavirus, and enterovirus were detected in both symptomatic and asymptomatic children. Because some viruses can be detected in children without symptoms, detection does not always implicate infection and usually will not affect management. These newer expensive tests may have utility in inpatient settings and for gathering epidemiologic data, but their use cannot be endorsed for the evaluation of children with respiratory symptoms in outpatient settings.

Editor Disclosures at Time of Publication

  • Disclosures for Deborah Lehman, MD at time of publication Nothing to disclose


Reader Comments (2)

Dennis Durante MD Physician, Pediatrics/Adolescent Medicine, Long Wharf Pediatrics, New Haven CT

Do the positive results in asymptomatic patients represent a viral carrier state, asymptomatic acute infection, or laboratory error from cross reactivity ?

Bsc, MB, ChB, PhD, FRCPath Physician, Infectious Disease, Mucropatholigy Ltd

The results overlap with our findings. The tests are not 'expensive' and that prejudice unfortunately biases the view here expressed. Unless we continue to monitor these admissions we will never learn more about the nature of host and parasite interactions.
We have found up to 4 viruses in some children and also associated bacteremia.

Your Comment

(will not be published)

Filtered HTML

  • Allowed HTML tags: <a> <em> <strong> <cite> <blockquote> <code> <ul> <ol> <li> <dl> <dt> <dd>
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Do you have any conflict of interest to disclose?
This question is for testing whether you are a human visitor and to prevent automated spam submissions.

Vertical Tabs

* Required

Reader comments are intended to encourage lively discussion of clinical topics with your peers in the medical community. We ask that you keep your remarks to a reasonable length, and we reserve the right to withhold publication of remarks that do not meet this standard.

PRIVACY: We will not use your email address, submitted for a comment, for any other purpose nor sell, rent, or share your e-mail address with any third parties. Please see our Privacy Policy.