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TacroType is a pharmacogenetic test designed to assess genetic variation in the CYP3A5 gene that affects how a transplant patient metabolizes tacrolimus. The test helps provide insights that transplant teams may use to inform dosing decisions from the very first dose.
Tacrolimus is one of the most widely utilized immunosuppressive drugs provided to transplant recipients today. Yet, early tacrolimus management is challenged by wide, patient-specific variability in drug metabolism, making it difficult to achieve therapeutic levels quickly and safely.1-4 Conventional tacrolimus dosing overlooks significant interpatient differences in metabolism, even among individuals of the same race.5,6 Because tacrolimus has a narrow therapeutic window, acute rejection or injury can result from misdosing.²
| Conventional dosing limitations | Impact on care |
|---|---|
| Relies on reactive adjustments rather than proactive management | May lead to prolonged time to reach therapeutic exposure and delay stabilization of immunosuppression |
| Standard approaches necessitate frequent drug monitoring and clinician-led titration | May increase demands on laboratory capacity, clinical staff time, and impact duration of patient stay |
| Does not account for interpatient variability in tacrolimus metabolism | Patients may experience repeated blood draws, dose changes, and uncertainty |
The TacroType test is a genotyping test that uses a buccal swab or blood sample to characterize CYP3A5 genotype information that healthcare providers may interpret and use to adjust tacrolimus dosing in their patients. The lab categorizes a patient as one of the following:
Our reports use interpretation standards aligned with CPIC (Clinical Pharmacogenetics Implementation Consortium) and DPWG (Dutch Pharmacogenetics Working Group) guidelines, helping ensure transplant teams receive current, evidence-based information.
TacroType provides:

Metabolism-based guidance using patient-specific genetic information

Genetic data to inform early tacrolimus dosing decisions in transplant patients

Genetic insights move beyond conventional dosing approaches

Information that may support clinical decision-making
Tacrolimus is predominantly metabolized by the cytochrome P450 3A (CYP3A) enzyme family, with CYP3A5 playing a key role in its oxidative metabolism in the liver and intestine.7 Genetic polymorphisms in the CYP3A5 gene result in differing levels of functional enzyme, which in turn can affect how rapidly tacrolimus is metabolized: individuals with at least one functional CYP3A5*1 allele (expressers) generally have lower dose-adjusted tacrolimus concentrations and may require higher doses to reach therapeutic trough levels compared with non-expressers (e.g., *3/*3 genotypes) who metabolize the drug more slowly.8 This genotype-associated variability partly explains the substantial inter-individual differences in tacrolimus pharmacokinetics seen in transplant recipients, and forms the basis of CYP3A5 genotype-guided dosing recommendations published by the Clinical Pharmacogenetics Implementation Consortium (CPIC).9

A third-party study has suggested that genotype-guided dosing improves achievement of target tacrolimus levels compared with standard dosing.10

One decision-tree model cites a ~$17K savings in total institutional costs associated with care when using CYP3A5 genotype-guided dosing for pediatric heart transplant patients.11

In one published analysis, pharmacogenomic-guided tacrolimus therapy was associated with ~ 6% fewer hospital-days and a lower incidence of adverse drug events, compared to standard dosing.12
We understand that time is of the essence in the pre-transplant period. TacroType is designed to be non-invasive, with a timely turnaround.
TacroType is a pharmacogenetic test designed to assess genetic variation in the CYP3A5 gene that affects how an organ transplant patient metabolizes tacrolimus.
No, TacroType is an adjunct to conventional dose monitoring methods. It helps provide patient-specific genotype data that may provide information regarding tacrolimus metabolism to aid in initial dosing decisions.
Test results are typically provided within 48 business hours from the time the sample is received. Turnaround times may vary.
TacroType uses a buccal swab or a blood sample for evaluation.
This assay detects the CYP3A5 *1, *3, *6, and *7 alleles, which may affect expression of the CYP3A5 enzyme responsible for tacrolimus metabolism. The genotype is used to predict metabolizer phenotype and guide initial tacrolimus dosing. On a report the lab categorizes a patient as one of the following:
Results should be interpreted by a licensed clinician in conjunction with therapeutic drug monitoring (TDM) and clinical factors.
The TacroType test results can help provide pharmacogenetic information relevant to tacrolimus metabolism. Individuals expressing CYP3A5 may require higher starting doses to achieve therapeutic drug concentrations compared with CYP3A5 non-expressers. Dosing considerations are based on CPIC and DPWG guidelines. Dose adjustments must be guided by measured tacrolimus trough levels, concomitant medications, and clinical response.
TacroType is performed by One Lambda Laboratories, a CLIA-certified facility specializing in high-complexity transplant diagnostics. Our laboratory operates with a robust quality management framework to help ensure that the results that you receive are analytically reliable and consistent with validated performance characteristics..
Incorporate genotype-informed tacrolimus dosing into your institutions protocols.
TacroType: Dose Smart from the Start.
For healthcare professional use only. TacroType is a laboratory developed test (LDT) performed by One Lambda Laboratories. This test has not been cleared or approved by the US FDA or CE marked in the EU. Clinical management must include therapeutic drug monitoring and comprehensive patient assessment.