I:T Ratio
I:T ratio = (bands + metamyelocytes + myelocytes) / (bands + metamyelocytes + myelocytes + neutrophils)
Bands, metamyelocyte, and myelocyte counts are given as part of the manual differentiation of white blood cell count from most laboratories.
Upper Limits of Normal
- Day 1
- 0.16
- Day 2
- 0.14
- Day 3 onward
- 0.12
If the I:T ratio is greater than 0.2 with a low neutrophil count or high CRP, infection is likely.