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Test Code 1829 Tacrolimus (FK506), Blood

Performing Laboratory

Barnes-Jewish Hospital Laboratory


Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Specimen Requirements

Specimen Type: Whole blood
Container/Tube: Lavender top (EDTA)-Green-top (lithium heparin) tube is not acceptable.

Specimen Volume: Full tube

Collection Instructions:

1. Draw blood for a peak level 1.5 to 4 hours after dose.

2. Draw blood for trough level immediately prior to next dose.

3. Label specimen appropriately (peak, trough, random).

Additional Information: Date and time of draw are required.

Day(s) Test Set Up

Monday through Sunday

Cut-off time: 2330, 0600, 0900, 1200

Turnaround Time:
STAT: not available

Routine: 3 hours after cut-off time

Reference Values

Results are reported in ng/mL.
The therapeutic range for tacrolimus can vary by transplant organ type and sample timing but a trough range of 5 - 15 ng/mL is typical.

Test Classification and CPT Coding


Additional Information

For BJH Laboratory Use Only

Alternate Tube(s):

1 pediatric, lavender-top (EDTA) tube

Analyte Stability:

Whole blood specimen is stable for up to 7 days ambient or refrigerated at 2° C to 8° C. For longer periods of storage, specimen should be frozen at -20° C. Mix freshly collected, refrigerated, or thawed specimen thoroughly prior to use. Avoid repeated freezing and thawing.

Laboratory Processing Instructions:

Test performed in BJH Chemistry.  Log in and place in the pending specimen refrigerator. Do not centrifuge. Do not freeze. Completed specimen is stored refrigerated for 1 week.

Specimen Transport Temperature

Ambient <7 days/Refrigerate OK

LOINC Code Information

Name LOINC Code
Tacrolimus 11253-2
Tacrolimus trough 33929-1