Specimen

Whole Blood

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

Preferred minimum:  3 mL whole blood in lavendar top tube (EDTA), mix 
well.
Absolute minimum:  1 mL whole blood

Specimen
Instructions:

Collect before next dose.

Testing Schedule:

Availability: one batch per day. Cutoff time for same day service is 
0900. Results available 1200 daily.

Analytic Time:

24 hours (upon receipt in laboratory)

Reference Range:

Therapeutic range 5-15 ng/ml

Test
Limitations:

The immunoassays are nonspecific and cross react with metabolites.
When elimination of tacrolimus is impaired (e.g. during cholestasis),
tacrolimus metabolites may accumulate.  The immunoassay may
overestimate the concentration of tacrolimus.  In such cases, the use
of a specific assay (e.g. HPLC/MS/MS) could be considered.  Specimens
from patients who have received preparations of mouse monoclonal
antibodies for diagnosis or therapy may contain human anti-mouse
antibodies (HAMA).  Such specimens may show either falsely elevated or
depressed values when tested with assay kits which utilize mouse
monoclonal antibodies.  These specimens should not be assayed with the
IMx Tacrolimus II assay.

Methodology:

MEIA (Microparticle Enzymatic ImmunoAssay)

CPT Code:

80197