[2] The CURB-65 is based on the earlier CURB score[3] and is recommended by the British Thoracic Society for the assessment of severity of pneumonia.
[6] It was shown that the PSI has a higher discriminatory power for short-term mortality, and thus is more accurate for low risk patients than the CURB-65 or its predecessor, the CURB score.
[3] However, the PSI is more complicated and requires arterial blood gas sampling amongst other tests; given this, the CURB-65 score is more easily used in primary care settings.
[7] A variant of the CURB-65 that omits the urea measurement (CRB-65)[7] is even simpler, as it relies only on history and examination findings rather than blood tests.
[citation needed] Patients with any type of infection (half of the patients had pneumonia), the risk of death increases as the score increases:[2]