The article presents a quick and accurate health literacy screening tool called the Newest Vital Sign (NVS), designed for use in primary care settings. The NVS is a nutrition label accompanied by six questions, taking about three minutes to administer. It is reliable, with Cronbach's alpha values of 0.76 in English and 0.69 in Spanish, and correlates with the Test of Functional Health Literacy in Adults (TOFHLA). The area under the ROC curve for the English version is 0.88, and for the Spanish version is 0.72. Patients with more than four correct answers are unlikely to have low literacy, while fewer than four correct answers suggest the possibility of limited literacy. The NVS was developed from scenarios involving health-related information, with five candidate scenarios refined based on feedback. The final version includes one scenario (a nutrition label) and six questions. It is the first literacy screening test available in both English and Spanish that can be administered in approximately three minutes. The NVS is reliable and accurate, with good sensitivity for detecting limited literacy. It is suitable for use as a quick screening test for limited literacy in primary health care settings. The study found that the NVS is more accurate than educational level or age in predicting literacy. The NVS is particularly effective in detecting limited literacy, with a score of less than four indicating the possibility of limited literacy. The study also highlights the importance of numeracy in health literacy, as the nutrition label scenario, which requires both reading and numeracy skills, was the best predictor of literacy. The NVS has advantages over currently available instruments, including being available in Spanish and being administered more quickly than the TOFHLA. The study also notes limitations, including the Spanish version having less good psychometric properties and the study population not being fully representative of all primary care practices. Future research should examine the validity of the NVS in other settings and whether it improves clinician-patient communication and health outcomes.The article presents a quick and accurate health literacy screening tool called the Newest Vital Sign (NVS), designed for use in primary care settings. The NVS is a nutrition label accompanied by six questions, taking about three minutes to administer. It is reliable, with Cronbach's alpha values of 0.76 in English and 0.69 in Spanish, and correlates with the Test of Functional Health Literacy in Adults (TOFHLA). The area under the ROC curve for the English version is 0.88, and for the Spanish version is 0.72. Patients with more than four correct answers are unlikely to have low literacy, while fewer than four correct answers suggest the possibility of limited literacy. The NVS was developed from scenarios involving health-related information, with five candidate scenarios refined based on feedback. The final version includes one scenario (a nutrition label) and six questions. It is the first literacy screening test available in both English and Spanish that can be administered in approximately three minutes. The NVS is reliable and accurate, with good sensitivity for detecting limited literacy. It is suitable for use as a quick screening test for limited literacy in primary health care settings. The study found that the NVS is more accurate than educational level or age in predicting literacy. The NVS is particularly effective in detecting limited literacy, with a score of less than four indicating the possibility of limited literacy. The study also highlights the importance of numeracy in health literacy, as the nutrition label scenario, which requires both reading and numeracy skills, was the best predictor of literacy. The NVS has advantages over currently available instruments, including being available in Spanish and being administered more quickly than the TOFHLA. The study also notes limitations, including the Spanish version having less good psychometric properties and the study population not being fully representative of all primary care practices. Future research should examine the validity of the NVS in other settings and whether it improves clinician-patient communication and health outcomes.