Abstract: The present invention provides methods and apparatuses related to measurement of analytes, including measurements of analytes in samples withdrawn from a patient.

Abstract: The present invention comprises methods and apparatuses that can provide accurate measurement of glucose or other analytes from a multilumen catheter in the presence of infusion of substances, including glucose. Examples of “multilumen catheters” include central venous catheters having multiple lumens, midline catheters having multiple lumens, multiple catheters configured or emplaced such that their lumens are in proximity to each other, and, in the case of indwelling analyte sensors, a catheter with a lumen for infusion and an indwelling sensor spaced apart from the infusion lumen. For blood withdrawal, anti-cross contamination controls can prevent the entrainment of blood which might be contaminated with feeding fluids or medications that are administered through other lumens within the catheter and in proximity of the blood sampling port. Cross contamination can occur under various situations, and is known to occur when the patient is connected to a ventilator.