Thermo Fisher Scientific has launched a new laboratory-developed test (LDT) to guide clinicians in their dosing of tacrolimus, a commonly prescribed immunosuppressant to lower the risk of organ rejection in transplant recipients.
Administering the correct dose of tacrolimus, most commonly known under the brand name Prograf in the US, at an early stage is important. If the dose is too low, the body may reject the new organ. If it is too high, patients are at an increased risk of injury, infection and other serious complications. Meanwhile, standard dosing approaches for tacrolimus are challenging because individual patients process the immunosuppressant differently based on factors including their genetic makeup.
Thermo Fisher’s TacroType pharmacogenetic test, designed for use in Clinical Laboratory Improvement Amendments (CLIA)-certified laboratories performing the test, provides genetic insights to help clinicians gain a clearer understanding of how each patient is likely to metabolise tacrolimus.
The test uses a swab sample to identify a patient’s CYP3A5 genotype, which influences how quickly tacrolimus is metabolised and how a patient may respond to therapy. The LDT is therefore positioned as a means for clinicians to make more informed dosing decisions to reduce the trial-and-error approach that has historically been relied upon.
“The TacroType test gives clinicians valuable information from the start and supports more effective, personalised care for patients during a critical period,” said Tina Liedtky, president of Thermo Fisher’s transplant diagnostics business.
“This new test reflects the growing role of pharmacogenetics in transplant medicine. It offers clinicians an additional datapoint to help manage immunosuppressive therapy to each patient’s unique needs,” Liedky added.
In September 2025, the US Food and Drug Administration (FDA) chose not to challenge a court ruling that dismissed the possibility of LDTs being regulated in the same way as medical devices.
In conversation with Medical Device Network at the time, Selena Yu, senior medical analyst at GlobalData, highlighted that the FDA’s decision not to challenge the court ruling was a positive outcome for the laboratory space.
Yu said: “Given all the budget cuts and delays being seen at the FDA this year [2025], the fact that LDTs are not going through the FDA may prove a net positive for innovation in the LDT space moving forward.”
