The calculator in question is the Diagnostic Criteria for Febrile Neutropenia. This is a clinical tool used primarily in the field of oncology and hematology, specifically for patients undergoing chemotherapy or other treatments that may suppress the immune system. 

Febrile neutropenia is a serious complication of chemotherapy characterized by a fever and a reduced number of neutrophils, a type of white blood cell that fights infection. The diagnostic criteria for febrile neutropenia are typically defined as a single oral temperature of ≥38.3°C (≥101°F) or a temperature of ≥38.0°C (≥100.4°F) sustained over a 1-hour period, along with a neutrophil count of <500 cells/mm³ or expected to fall below 500 cells/mm³ within the next 48 hours.

The clinical utility of this calculator is to help clinicians identify patients who are at risk of developing serious infections due to their low neutrophil count and fever. Early identification of febrile neutropenia can lead to prompt initiation of antibiotic therapy, which can significantly improve patient outcomes.

There are no specific exclusion criteria for the use of this diagnostic criteria. However, it is primarily applicable to patients undergoing treatments that suppress the immune system,

Diagnostic criteria for febrile neutropenia

# Criteria
 # Fever
A. Single oral temperature measurement of >= 38.3 degrees C (101 degrees F)
B. Temperature of >= 38.0 degrees C (100.4 degrees F) sustained over a 1-hour period
# Neutropenia
C. Absolute neutrophil count <= 500/mcL
D. Absolute neutrophil count expected to decrease to < 500/mcL during the next 48 hours

# Conditions
- (A or B) and (C or D)
- true

Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america.