Investigations

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Investigations

In most infants presenting to hospital and/or hospitalised with bronchiolitis, no investigations are required. Guidance for the use of chest Xray (CXR), laboratory and virological testing are outlined below. 

Chest Xray 

Do not routinely use CXR in infants presenting or admitted to hospital with bronchiolitis. (Evidence quality: very low; recommendation strength: conditional)

CXR may be considered in the following situations:

  1. Infants with an unexpected deterioration* (defined as an unexpected requirement for an escalation of care), and/or a clinical course not consistent with bronchiolitis, including concerns regarding the presence of sepsis, pneumonic consolidation, pneumothorax, empyema, immunodeficiency, pleural effusion, or significant cardiac abnormalities. (Evidence quality: NA; recommendation strength: consensus-based)

     
    *The following are not considered “unexpected deterioration”: gradual development of an oxygen requirement, increased work of breathing, and/or the need for humidified high flow (HF) therapy in the first few days of illness.

  2. In infants presenting with bronchiolitis in high dependency unit (HDU) or ICU settings, where there is clinician diagnostic concern regarding possible sepsis, pneumonic consolidation, pneumothorax, empyema, immunodeficiency, pleural effusion, or significant complication of other diseases (e.g., heart failure with congenital heart disease), in order to guide treatment options. (Evidence quality: NA; recommendation strength: consensus-based)

Laboratory tests

Do not routinely use laboratory tests for infants presenting or admitted to hospital with bronchiolitis, including bacteriological testing of urine or blood. (Evidence quality: very low; recommendation strength: conditional)

However, clinicians may consider glucose and/or sodium levels during assessment in infants with bronchiolitis and poor feeding, evidence of dehydration or altered mental state. (Evidence quality: NA; recommendation strength: consensus-based)

Clinicians may consider using biomarkers (full blood count, C-reactive protein, procalcitonin) and blood cultures to inform diagnoses of serious bacterial co-infection in the following groups:

  1. Infants with an unexpected deterioration (defined as an unexpected requirement for an escalation of care) during their hospitalisation with bronchiolitis. (Evidence quality: NA; recommendation strength: consensus-based).

  2. Infants admitted to the ICU with bronchiolitis. (Evidence quality: very low; recommendation strength: weak).

Urine testing may also be considered to inform a diagnosis of serious bacterial co-infection in infants with an unexpected deterioration during hospitalisation for bronchiolitis. 

Virological tests

Do not routinely use viral testing in infants presenting or admitted to hospital with bronchiolitis, including testing undertaken solely for cohorting of patients. (Evidence quality: very low; recommendation strength: conditional) 

This recommendation is separate from the requirements for virological testing that hospitals may have. Routine viral testing is unlikely to provide benefit to individual infants but provides epidemiological data.