Disclosed is a system that samples a body fluid of a patient. The system includes a fluid handling system (10) having one or more fluid passageways. The system further includes a pump system for infusing an infusion fluid by way of a fluid handling system into a patient (P) through one or more fluid passageways . The system further includes a pump system for obtaining a sample of body fluid by way of a fluid handling system from a patient through one or more fluid passageways. The obtained sample is no more than 5 milliliters in volume. The system further includes an analyzer (140) for analyzing at least an analyzed portion of the obtained sample by way of an analyte detection system operatively associated with the fluid handling system to determine a concentration of at least one analyte.