CURB-65 and qSOFA: separate score formulas with boundary tests

Two distinct educational calculations

Use fictional adult observations. These formulas demonstrate threshold logic; they are not validated clinical software and do not decide admission, discharge, ICU care or treatment. A low result does not rule out serious disease.

CURB-65 for adult community-acquired pneumonia combines confusion, urea above 7 mmol/L, breathing rate at least 30/min, low blood pressure and age at least 65. The confusion flag represents AMT at most 8 or new disorientation. Clinical judgement remains necessary.

qSOFA uses respiratory rate at least 22/min, systolic pressure at most 100 mmHg and altered mentation, represented here by GCS below 15. It is not a sepsis diagnosis. Surviving Sepsis Campaign recommends against qSOFA as the sole sepsis screening tool.

CURB-65: use urea in mmol/L and count pressure only once

B3 is urea in mmol/L, not BUN in mg/dL. OR combines systolic below 90 and diastolic at most 60 into one point. Do not substitute an approximately converted rounded threshold. B2 is an independently supplied 0/1 confusion flag.

=IF(COUNT(B2:B7)<>6,"Invalid inputs",IF(OR(AND(B2<>0,B2<>1),B3<=0,B4<=0,B5<=0,B6<=0,B7<18,B7<>INT(B7)),"Invalid inputs",B2+IF(B3>7,1,0)+IF(B4>=30,1,0)+IF(OR(B5<90,B6<=60),1,0)+IF(B7>=65,1,0)))

qSOFA: use a separate GCS input

B8 is a whole Glasgow Coma Scale total from 3 through 15, supplied independently. The CURB confusion criterion is not automatically interchangeable with GCS. This formula intentionally does not need the urea or age cell; it assumes an adult educational case.

=IF(OR(COUNT(B4:B5)<>2,COUNT(B8)<>1),"Invalid inputs",IF(OR(B8<3,B8>15,B8<>INT(B8),B4<=0,B5<=0),"Invalid inputs",IF(B8<15,1,0)+IF(B4>=22,1,0)+IF(B5<=100,1,0)))

Further reading

• Microsoft Support — OR function
• NICE NG250 — CURB65 and clinical judgement
• Sepsis-3 consensus definitions
• Surviving Sepsis Campaign 2021 — screening recommendations