Misleading tacrolimus concentration value in blood taken from a catheter used for tacrolimus administration

Am J Health Syst Pharm. 2008 Feb 1;65(3):226-8. doi: 10.2146/ajhp070054.


Purpose: A misleading blood tacrolimus concentration (BTC) value caused by the contamination of a central venous catheter previously used for tacrolimus administration is described.

Summary: A 59-year-old woman with severe chronic obstructive pulmonary disease successfully underwent double lung transplantation. In the intensive care unit, she received a continuous i.v. infusion of tacrolimus from days 1 to 5 after transplantation through the distal lumen of a polyurethane triple-lumen central venous catheter. The catheter lumen was flushed twice a day with 0.9% sodium chloride injection. The proximal lumen was used for blood sampling after being flushed; the first 10 mL of blood was discarded. BTCs determined in whole blood one, four, and five days after transplantation were within the therapeutic range of 5-15 ng/mL. On day five the patient was transferred to the thoracic surgery ward and was switched to oral tacrolimus 1.5 mg twice daily. The BTC on day 6 was unexpectedly high at 134.5 ng/mL. The patient's clinical status was normal, and no signs of tacrolimus toxicity were observed. On day 7, blood samples were drawn from a peripheral vein and simultaneously through the central venous catheter. Although the central venous catheter had not been exposed to tacrolimus during the preceding two days, it yielded blood with a BTC eight times higher than the BTC in blood from the peripheral vein (41.4 ng/mL versus 5.1 ng/mL).

Conclusion: The collection of blood from a central venous catheter lumen that had been used for tacrolimus administration resulted in a BTC about eight times higher than what was measured in peripheral blood.

Publication types

  • Case Reports

MeSH terms

  • Catheterization, Central Venous*
  • Female
  • Humans
  • Immunosuppressive Agents / administration & dosage
  • Immunosuppressive Agents / blood*
  • Immunosuppressive Agents / pharmacokinetics
  • Lung Transplantation
  • Middle Aged
  • Tacrolimus / administration & dosage
  • Tacrolimus / blood*
  • Tacrolimus / pharmacokinetics


  • Immunosuppressive Agents
  • Tacrolimus