CSU Graduate School requires that proficiency in the English language be demonstrated either by the TOEFL, IELTS, Duolingo, or and PTE Academic tests prior to admission.
TOEFL minimum score – 550 (paper based), 80 (Internet based)
IELTS minimum score – 6.5
Duolingo minimum score – 120
PTE minimum score – 58
Note: Your department may have higher TOEFL/IELTS/Duolingo/PTE score requirements.
https://international.colostate.edu/iec/international-admissions/english-language-proficiency/