Measuring health literacy efficiently yet accurately is of interest both clinically and in research. The authors examined 6 brief health literacy measures and compared their categorization of patient health literacy levels and their comparative associations with patients' health status. The authors assessed 400 emergency department patients with the Short Test of Functional Health Literacy in Adults, the Newest Vital Sign, Single Item Literacy Screen, brief screening questions, Rapid Estimate of Adult Literacy in Medicine-Revised, and the Medical Term Recognition Test. The authors analyzed data using Spearman's correlation coefficients and ran separate logistic regressions for each instrument for patient self-reported health status. Tests differed in the proportion of patients' skills classified as adequate, but all instruments were significantly correlated; instruments targeting similar skills were more strongly correlated. Scoring poorly on any instrument was significantly associated with worse health status after adjusting for age, sex and race, with a score in the combined inadequate/marginal category on the Short Test of Functional Health Literacy in Adults carrying the largest risk (OR = 2.94, 95% CI [1.23, 7.05]). Future research will need to further elaborate instrument differences in predicting different outcomes.