Slightly elevated relative neutrophils (70.3%) but normal absolute neutrophils (4.5, with 1.3-7.0 being lab reference range). infection likely?

Not likely: It all depends on your symptoms, cultures, etc, but your neutrophil count is normal.

Nonspecific: Laboratory tests and blood work all have to be interpreted in a clinical context. In short this means that not all labs are 100% accurate - a high neutrophil percentage may be indicative of infection, but not always. 70% is not a very high number :)