blood tests are critical to immunosuppressive therapy
by Neoteryx | 3 min read
The human immune system is conditioned to attack anything it identifies as "foreign." When a patient receives an organ transplant, their immune system typically identifies the new organ as foreign, and will reject it. Immunosuppressive therapy is prescribed to organ transplant patients to reduce this risk. These drugs suppress the body’s natural immune response. Therefore, organ transplantation is followed by immunosuppressive therapy that lasts a lifetime. Immunosuppressive drug treatment ensures organ survival by minimizing the chances of the patient's body rejecting it. Immunosuppressives are also prescribed for patients with certain autoimmune disorders, and other conditions that trigger an overactive immune system response.
Immunosuppressive drugs need constant monitoring to help the care team avoid administering doses that are too high or too low. High doses can be toxic, leading to side effects and complications. Small doses can increase the risk of organ rejection. Therapeutic drug monitoring (TDM) plays a pivotal role in the management of immunosuppressive therapy, ensuring that the right drug concentrations are achieved and maintained for each individual patient.
TDM usually involves drawing whole blood, plasma, or serum samples and testing them at regular intervals to assess drug concentration levels in the bloodstream. TDM helps physicians adjust dosages and individualize a therapeutic regimen for each unique patient. Frequent blood testing and analysis help the care team identify and track any inter-individual variations between the dose and its effect.
If a patient exhibits significant pharmacokinetic variation, the drug dosage may need to be adjusted. This can be challenging. Certain immunosuppressive drugs have a narrow target range and high intra- and inter-subject variability. These drugs include mycophenolic acid, cyclosporine, tacrolimus, sirolimus, everolimus, and prednisolone. Routine blood testing at regular intervals for TDM is critical for patients taking these medications.
TDM Can Be Burdensome for Patients
For immunosuppressive drug monitoring, blood samples have traditionally been obtained through venipuncture blood draws in the clinic or lab. This method has presented challenges and limitations, the most notable being the invasive nature of the sample collection. Many patients find it stressful and painful to have blood drawn from a vein in their arm. What’s more, since TDM for many patients is ongoing, they need to visit the clinic frequently to undergo this phlebotomy procedure. This can mean frequent travel and many days of missed school or work, and a lot of stress.
Remote, Patient-Friendly Blood Collection Is a Game-Changer
Remote blood sample collection methods have been developed to minimize patient discomfort and inconvenience. Remote blood sampling can be performed by patients at home, and involves the collection of small capillary blood samples from a fingertip. Remote samples can be mailed to a lab for testing.
Improvements in molecular analysis have reduced the need for collecting large blood samples in tubes for TDM. Sample sizes <100 uL can be used for analysis. Smaller samples address the limitations in conventional techniques by enhancing the potential for fast, cost-effective, and less-invasive collection procedures.
The advantages of patient-centric, remote blood sampling reach beyond therapeutic drug monitoring. Frequent and large-volume blood sampling is uncomfortable for most patients, especially those with chronic illnesses that require regular blood draws. Remote blood sampling enables remote patient monitoring of people living with liver disease, diabetes, cancer, and other conditions.
Volumetric absorptive microsampling (VAMS®) is the novel remote blood-sampling approach proving most effective in collecting blood samples at home, especially for patients undergoing immunosuppressive therapy. The technique involves using a Mitra® device with an absorptive tip to collect small, precise blood volumes. The patient uses a simple finger-stick method to draw a drop of capillary blood from the fingertip and absorb it onto the Mitra.
The blood samples dry right on the Mitra device tip, and are sent to the lab for analysis as a dried blood sample. VAMS is fast, cost-effective, and improves reliability because it provides fixed volumes of blood for accurate analysis. Patients don’t need to visit the clinic for blood draws; the method promotes self-sampling with minimal training.
At-home kits like the Mitra® Blood Collection Kit include the Mitra microsampler, lancets, bandages, gauze, desiccant, a foil pouch and shipping envelope, and easy instructions for use. At-home sampling means that patients no longer need to disrupt their routines to visit clinics for painful blood draws. Their care team must order a Mitra blood collection kit that can be shipped to patients at their home address.
This remote blood sampling method is suitable for patients undergoing immunosuppressive therapy for conditions such as ulcerative colitis, autoimmune diseases (Crohn’s disease, psoriasis, multiple sclerosis), organ transplants, and vasculitis, among others.