title: Study of the correlation between MEIA and ELISA methods for FK 506 determination in liver transplant recipients.
abstract: OBJECTIVE
  FK 506 is an immunosuppressive macrolide advocated for prevention of graft rejection. Plasma or blood FK 506 levels must be determined to strike a balance between FK 506 toxicity and graft rejection. The first aim of this study was to compare an automated microparticle enzyme immunosorbent assay (MEIA) method (on whole blood) with the reference enzyme-linked immunosorbent assay (ELISA) method (on plasma). A second aim was to compare the two methods for prediction of FK 506 nephrotoxicity.
  
  
  METHODS
  Forty-seven patients were studied comprising 128 samples. All were treated with FK 506 on a compassionate basis. For each patient, the concentrations of FK 506 were determined in plasma by means of ELISA and in whole blood by MEIA.
  
  
  RESULTS
  The repeatability and the reproducibility of these two methods were similar. The inter-patient correlation coefficient between MEIA and ELISA, determined on 128 samples from 47 liver recipients, was satisfactory (r = 0.82). From these 47 patients, the intra-patient correlation coefficients were calculated for 17 of them. The intra-patient correlation coefficients were between 0.63 and 0.98 for 15 patients, and between 0.26 and 0.55 in the remaining two cases. Mean creatinine plasma levels in the 55 samples below the median FK 506 value in the MEIA method and in the 55 with values above the median (120 and 134 mumol/litre, respectively) were significantly different (P < 0.05), as were those using the reference ELISA methods (115 and 139 mumol/litre, P < 0.01). In contrast, there was no significant difference between the mean creatinine plasma levels in the 55 samples with FK 506 levels below the median using both methods or between those above the median.
  
  
  CONCLUSIONS
  The automated MEIA method, being simpler and more rapid than the ELISA method, should now be preferred for therapeutic monitoring of FK 506.
authors.affiliation: Laboratoire de pharmacocinétique, Service de Pharmacie, Couturier, Villejuif, France.
authors.forename: E
authors.initials: E
authors.lastname: Rudant
authors.forename: Y
authors.initials: Y
authors.lastname: Bezie
authors.forename: L
authors.initials: L
authors.lastname: Bonhomme-Faivre
authors.forename: N
authors.initials: N
authors.lastname: Manuel
authors.forename: P
authors.initials: P
authors.lastname: Rucay
authors.forename: G
authors.initials: G
authors.lastname: Fredj
authors.forename: H
authors.initials: H
authors.lastname: Bismuth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood* / Q000493:pharmacokinetics; D016031:Liver Transplantation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D013223:Statistics as Topic; D016559:Tacrolimus / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D007166:Immunosuppressive Agents; D016559:Tacrolimus