Series Research On Tacrolimus Whole Blood Concentration Determined By Chemiluminesent Microparticle Immunoassay In Liver Transplant Recipients

Objective: To investigate the quality and influencing factors oftacrolimus whole blood sample assay by Chemiluminesent MicroparticleImmunoassay (CMIA), establish the quality control method for therapeuticdrug monitoring of tacrolimus. Investigating the rationality of tacrolimustrough concentration (C0) reference range and influencing factors on relativeclearance (RC) of tacrolimus in liver transplant recipients, provide referencefor clinical individualized medication.Methods:1The precision and recovery of monitoring tacrolimus bloodconcentration by CMIA method were studied.Make Levey-Jennings qualitycontrol graphs with control data from november2011to november2012.The monitoring results of tacrolimus between whole blood samplesstored in5℃,20℃,26℃for1day,3days and the control group werecompared in order to investigate the influence of storage tempreture and time.The impact of using AXSYM sample tube and transplant pretreatment tubewas studied,so was the influence of storage time in transplant pretreatmenttube.2Retrospective analysis of305tacrolimus C0in74liver transplantrecipients from November2011to April2012was made. The clinialpresentations and biochemical indexes were observed to help to investigate thereference range of tacrolimus C0in liver transplant recipients.3Tacrolimus C0were monitored for82liver transplant recipients fromNovember2011to November2012in our hospital.Among the82liver transplant recipients, there were34who were in thefirst month posttransplant and treated with “tacrolimus+mycophenolate mofetil+prednison”.Observe the following indicators：dose(D) and C0oftacrolimus, albumin(ALB), glutamic-pyruvic transaminase(ALT), totalbilirubin(TBIL), glucose(GLU), creatinine(Cr), white blood cell(WBC), redblood cel（lRBC）, platele（tPLT），hematocri（tHCT）.The relationship betweenthese biochemical indicators and RC were assessed using the Pearsoncorrelatin analysis.Among the82liver transplant recipients, there were9who had anepisode of diarrhea.Combine the information of diarrhea occurred time andduration with CR to investigate the influence of diarrhea on tacrolimus CR.Results:1The RSD for the intraday and interday assays of AbbottImmunosuppresant-MCC Level1(4.2ng/ml)、Level2(8.7ng/ml)、Level3(18.2ng/ml) were0.60%,0.22%,0.09%;1.38%,0.47%,0.10%respectively;the recovery rate for the intraday and interday assays were104.38%,103.85%,103.11%;102.86%,102.14%,103.11%respectively.The recovery rate andprecision of monitoring tacrolimus whloe blood concentration by CMIAconform to the requirements of “Chinese Pharmacopoeia” that biologicalsample testing RSD <15%, method recovery rate between85~115%.There were91tacrolimus control data determined together with thepatient samples from November2011to November2012. All of the91controldata were within our control.Control graph of AbbottImmunosuppresant-MCC Level1and3were in good condition,howevercontrol graph of Level2wasn’t because of different lot number.A study in11patients’ tacrolimus whole blood sample showed that, therewere no significant statistic difference between the samples stored in5℃for1day,3days,26℃for1day and the control group (P>0.05), there wassignificant statistic difference between the samples stored in26℃for3day(P<0.05).There were no significant statistic difference between the monitoringresults of samples in AXSYM Sample Tube and Transplant Pretreatment Tube(P>0.05).There were no significant statistic difference between samples in Transplant Pretreatment Tube tested at once and0.5hour later (P>0.05),butwith difference of higher results tested3hours later (P<0.05).2305tacrolimus C0in74liver transplant recipients were determined byCMIA from November2011to April2012.The blood trough level of Tacrolimus was7.0±3.6ng/mL within thefirst three months,5.5±2.3ng/mL from the third month after transplantation.There were4case-times of acute rejection and54case-times of drugtoxicity.The incidence of drug toxicity increased along with tacrolimusC0.Before and after the third month of transplantation,there were only16.5%and51.9%tacrolimus C0within the primary reference range, so the referencerange was adjusted as following:8~15ng/mL within the first three months,5~10ng/mL from the third month after transplantation.3157tacrolimus C0were monitored for34recipients in the first monthafter liver transplantation.During this period, mean value of D, C0,RC, ALB,ALT, TBIL, GLU, Cr, WBC, RBC, PLT, HCT was0.058±0.014mg/kg,7.2±2.7ng/ml,9.2±4.2L/kg,38.3g/L,147U/L,52umol/L,6.5mmol/L,74umol/L,9.1×10~9/L,3.4×10~9/L,131×10~9/L,32.1%respectively.ALT,TBIL,GLUwere above the referecne range;RBC, HCT were blow the referecne range，therest were normal.There was negative correlation between TBIL,GLU,HCTand RC (r=0.357for TBIL, r=0.366for GLU, r=0.349for HCT).Among the82liver transplant recipients, there were9who had anepisode of diarrhea,the incidence of diarrhea was11.0%. RC decline wasobserved in5of them（55.6%）, RC declined47%on average，3recipients haddose ajustment for diarrhea.Conclusion:1CMIA is suitable for clinical therapeutic drug monitoring of tacrolimuswhole blood concentration with high precision and low limit ofquantification.Proper quality control method should be applied to guaranteethat the monitoring results were accurate and trustworthy.Tacrolimus whole blood sample can be stored under5℃or20℃for3days and26℃for just1day without influence on monitoring results. When stored under26℃for3days,the monitoring results would be inaccurate.Samples can be tested in AXSYM Sample Tube or Transplant PretreatmentTube,and the former is more economical.Extracted sample in TransplantPretreatment Tube within30minutes can be tested again,while extractedsample in Transplant Pretreatment Tube beyond3hours can’t be tested again.2The reference range of tacrolimus C0should be ajusted as follows:8～15ng/mL within the first three months,5～10ng/mL from the third month afterliver transplantation.3There is negative correlation betweenTBIL,GLU,HCT and RC in thefirst month after liver transplant procedure.So,when TBIL,GLU,HCTchange,it reminds us the fluctuation of RC.For liver transplant recipients who have an episode of diarrhea,dosetitration should be careful to avoid rejection, even though they probably havethe decrease of tacrolimus RC and increase of tacrolimus C0.