Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 42 (1), 3-15

The Reliability of the Glasgow Coma Scale: A Systematic Review


The Reliability of the Glasgow Coma Scale: A Systematic Review

Florence C M Reith et al. Intensive Care Med.


Introduction: The Glasgow Coma Scale (GCS) provides a structured method for assessment of the level of consciousness. Its derived sum score is applied in research and adopted in intensive care unit scoring systems. Controversy exists on the reliability of the GCS. The aim of this systematic review was to summarize evidence on the reliability of the GCS.

Methods: A literature search was undertaken in MEDLINE, EMBASE and CINAHL. Observational studies that assessed the reliability of the GCS, expressed by a statistical measure, were included. Methodological quality was evaluated with the consensus-based standards for the selection of health measurement instruments checklist and its influence on results considered. Reliability estimates were synthesized narratively.

Results: We identified 52 relevant studies that showed significant heterogeneity in the type of reliability estimates used, patients studied, setting and characteristics of observers. Methodological quality was good (n = 7), fair (n = 18) or poor (n = 27). In good quality studies, kappa values were ≥0.6 in 85%, and all intraclass correlation coefficients indicated excellent reliability. Poor quality studies showed lower reliability estimates. Reliability for the GCS components was higher than for the sum score. Factors that may influence reliability include education and training, the level of consciousness and type of stimuli used.

Conclusions: Only 13% of studies were of good quality and inconsistency in reported reliability estimates was found. Although the reliability was adequate in good quality studies, further improvement is desirable. From a methodological perspective, the quality of reliability studies needs to be improved. From a clinical perspective, a renewed focus on training/education and standardization of assessment is required.

Keywords: Glasgow Coma Scale; Glasgow Coma Score; Grading scales; Reliability; Reproducibility of results; Systematic review.

Similar articles

See all similar articles

Cited by 19 articles

See all "Cited by" articles


    1. Lancet. 1991 Mar 2;337(8740):535-8 - PubMed
    1. Ann Neurol. 2005 Oct;58(4):585-93 - PubMed
    1. Crit Care Med. 2000 Feb;28(2):389-94 - PubMed
    1. J Trauma. 1996 Sep;41(3):514-22 - PubMed
    1. Can J Neurol Sci. 2009 Jul;36(4):429-35 - PubMed

MeSH terms

LinkOut - more resources