Sampling instructions

Sampling should be done prior to the injection/infusion of the drug during the day of scheduled (or up to 24 hours before) drug administration. The sample should be taken when the concentration of the drug is expected to be as low as possible (the "Cmin at steady state" or "trough" levels). "Cmin" corresponds to the minimum drug concentration at "steady state" when the variation of drug concentration in the serum is the lowest and provides the highest sensitivity for detection of NAbs. At detectable levels of the drug, the presence of NAbs is considered to be of low therapeutic significance.

Blood samples are collected in a tube with no additive or in a gel tube. Both venous and capillary samples can be analyzed. The sample should be left to coagulate for minimum of 30 minutes at ambient temperature and then centrifuged. Serum is separated and transferred to a new tube carefully marked with patient identification. The serum sample should be kept refrigerated awaiting transport, which can be done at room temperature by ordinary mail. If the sample is not sent directly it should be stored in a refrigerator (2-10° C for up to one week) or freezer (approximately -20° C for longer time periods) awaiting transport. Approximately 3 mL of serum should be sent, a smaller volume for children is acceptable.

Print and complete the request form and send it together with the sample.