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Updated: Apr 3, 2026
Diffuse Reflectance Spectroscopy: Getting the Capillary Refill Test Under One's Thumb
Published on: December 2, 2017
The Diagnostic Value of Capillary Refill Time for Detecting Serious Illness in Children: A Systematic Review and
Susannah Fleming1, Peter Gill2, Caroline Jones1
1Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, Oxfordshire, United Kingdom.
Insights
Capillary refill time (CRT) is a specific indicator of serious illness in children, with prolonged CRT indicating a four-fold increased risk of mortality. However, normal CRT should not rule out serious conditions due to low sensitivity.
Area of Science:
- Pediatric Emergency Medicine
- Diagnostic Accuracy
- Clinical Assessment
Background:
- Capillary refill time (CRT) is a standard assessment for unwell children.
- Its diagnostic value for serious outcomes requires further evaluation.
Purpose of the Study:
- To determine the diagnostic accuracy of CRT for various serious outcomes in pediatric patients.
- To assess CRT's utility as a screening tool in pediatric emergency care.
Main Methods:
- Systematic review and meta-analysis of studies published up to June 2014.
- Included studies assessed CRT and clinical outcomes (mortality, dehydration, meningitis, etc.) in children up to 18 years.
- Hierarchical summary ROC curves were constructed where data permitted.
Main Results:
- Meta-analysis for mortality showed high specificity (92.3%) but low sensitivity (34.6%) for CRT.
- CRT demonstrated high specificity for dehydration (89-94%), but sensitivity varied widely (0-94%).
- Consistently high specificity was observed for other serious conditions like meningitis, sepsis, and hypoxia.
Conclusions:
- Capillary refill time is a specific clinical sign, acting as a 'red-flag' for serious illness.
- Prolonged CRT is associated with a significantly increased risk of mortality.
- Low sensitivity indicates that a normal CRT reading should not exclude serious pathology.
Importance:
Capillary refill time (CRT) is widely recommended as part of the routine assessment of unwell children.
Objective:
To determine the diagnostic value of capillary refill time for a range of serious outcomes in children.
Methods:
We searched Medline, Embase and CINAHL from inception to June 2014. We included studies that measured both capillary refill time and a relevant clinical outcome such as mortality, dehydration, meningitis, or other serious illnesses in children aged up to 18 years of age. We screened 1,265 references, of which 24 papers were included in this review. Where sufficient studies were available, we conducted meta-analysis and constructed hierarchical summary ROC curves.
Results:
Meta-analysis on the relationship between capillary refill time and mortality resulted in sensitivity of 34.6% (95% CI 23.9 to 47.1%), specificity 92.3% (88.6 to 94.8%), positive likelihood ratio 4.49 (3.06 to 6.57), and negative likelihood ratio 0.71 (0.60 to 0.84). Studies of children attending Emergency Departments with vomiting and diarrhea showed that capillary refill time had specificity of 89 to 94% for identifying 5% dehydration, but sensitivity ranged from 0 to 94%. This level of heterogeneity precluded formal meta-analysis of this outcome. Meta-analysis was not possible for other outcomes due to insufficient data, but we found consistently high specificity for a range of outcomes including meningitis, sepsis, admission to hospital, hypoxia, severity of illness and dengue.
Conclusions:
Our results show that capillary refill time is a specific sign, indicating that it can be used as a "red-flag": children with prolonged capillary refill time have a four-fold risk of dying compared to children with normal capillary refill time. The low sensitivity means that a normal capillary refill time should not reassure clinicians.
