An evaluation of the reliability and validity of capillary refill time test
Abstract
Background
While capillary refill time test (CRTT) has been commonly used as a quick and convenient clinical vascular assessment of the lower limb, the validity of this test has not been established.
Objectives
There were three aims to this study: the first was to evaluate the reliability of CRTT, the second to investigate the premise that CRTT represents skin perfusion, and thirdly to determine whether CRTT can detect lower limb vascular disease.
Method
Intra- and inter-tester reliability was evaluated for five experienced physicians who used CRTT on 10 participants. Criterion validity for measurement of skin perfusion was investigated by comparison with laser Doppler flowmetry on 49 participants, and for this same group the usefulness of detecting those persons with peripheral arterial disease and a state of impaired healing was evaluated.
Results
CRTT had reasonable intra-tester reliability (ICC=0.72) but poorer inter-tester reliability (ICC range=0.12–0.81). For measurement of skin perfusion, CRTT was predictive of only 38% of the variance in laser Doppler flowmetry measures (r2=0.38, P<0.001). Finally, CRTT was not able to discriminate between patients with and without peripheral arterial disease (z=−1.86, P=0.062), nor could it discern between patients with and without impaired lower extremity healing (z=−0.21, P=0.830). Laser Doppler flowmetry was also unable to predict the presence of peripheral arterial disease (t96=0.27, P=0.787) and impaired healing (t96=1.95, P=0.054).
Conclusion
These results question the usefulness of capillary refill time test for assessment of vascular status in the lower limb.
aSchool of Biomedical and Health Sciences, B24 Campbelltown Campus, University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW 1797, Australia
bAcademic Unit of Musculoskeletal Disease, University of Leeds, Chapel Allerton Hospital, Chapeltown Rd, Leeds LS7 4SA, United Kingdom
ABSTRACT