Performance of a no-pretreatment tacrolimus assay on the Dade Behring Dimension RxL clinical chemistry analyzer.
BACKGROUND
Therapeutic drug monitoring for tacrolimus is important for organ transplant patients receiving this immunosuppressant. Current available assays for tacrolimus require sample pre-treatment and operate in a batch mode. Here a no-pretreatment tacrolimus assay, performed on the Dade Behring Dimension analyzer is compared to the Abbott IMx tacrolimus assay and to an LC/MS/MS method.


METHODS
Whole blood samples from 2 medical centers and different transplant types (kidney n=103, liver n=81, heart n=27, pancreas n=16, bone marrow n=9, [corrected] lung n=7), were obtained and tacrolimus quantified by each of the 3 assays.


RESULTS
The lower limit of the linear range was 1.2 ng/ml on the Dimension assay. Total imprecision was 9.8% and within-run imprecision was 9.6% at a tacrolimus concentration of 3.4 ng/dL. Passing-Bablock regression analysis determined the following relationships: DIMN=(1.16) LC/MS - 0.43, r=0.90 and DIMN=(0.99)IMx - 0.35, r=0.87.


CONCLUSIONS
The Dade Behring Dimension [corrected] Tacrolimus assay has adequate imprecision and correlates well with the reference method of LC/MS/MS. The assay appears suitable for clinical use, and has the advantages of not requiring a pretreatment step and the ability to be performed in a random-access mode.
Griffey
Megan A
MA
Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, MO 63110-1093, USA.
Hock
Karl G
KG
Kilgore
Daniel C
DC
Wei
Tie Q
TQ
Duh
Show-Hong
SH
Christenson
Robert
R
Scott
Mitchell G
MG
D002853:Chromatography, Liquid; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods*; D007166:Immunosuppressive Agents / Q000097:blood*; D013058:Mass Spectrometry; D016377:Organ Transplantation; D016559:Tacrolimus / Q000097:blood*
D007166:Immunosuppressive Agents; D016559:Tacrolimus