Expert opinions? which diagnostic test result identifies the patient as being at risk for sepsis?

Clinical acumen: Experts can't wait for labs to come back to make decisions for sepsis. If there is a source of infection, if there is fever over 101-101.5, respiratory rate deemed to be fast, heart rate 20 points more than pt's usual or deemed tachycardic, relative hypoxia or increased a-a gradient calculated to age, the labs including WBC count can wait and simply looking at pt, a DX of sepsis can safely be made.

Clinical diagnosis: Sepsis is a clinical diagnosis - there is no lab test for sepsis. Lab tests are used to assist in the diagnosis of sepsis. Look at the SOFA score to see how clinical information is put together to determine if someone has sepsis https://en.wikipedia.org/wiki/SOFA_score The SOFA score uses vital signs, physical exam, and lab tests to help determine if someone has sepsis