test Details

Tacrolimus Toxicity, Transplantation Rejection, Kidney Damage

The Tacrolimus Test is used for measuring the current levels of Tacrolimus, an immunosuppressive drug, in the body.

Tacrolimus immunosuppressive drug is slowly introduced in those patients who are being prepared to undergo any kind of organ transplantation. Tacrolimus drug is known to have clinical benefits that help the body not reject the new organ that has been transplanted into it.

The drug works by suppressing the activity of the immune system of the body that has just received a foreign organ through a transplant. By reducing the immune system’s activity, the Tacrolimus drug reduces the chances of the body rejecting the new organ, thereby preventing severe health consequences.

So, Tacrolimus drug is given to patients before the surgery is supposed to happen to monitor the amount of drug that suits and works well on the patient’s body.

Tacrolimus Test is used to ensure that your body is receiving a dosage of the drug that falls within a previously specified clinical range or the ‘therapeutic range.’ Since the clinical range associated with the dosage of Tacrolimus drug is usually a very narrow range, healthcare practitioners have to be wary of how even the smallest change in the drug dosage is being taken by the body.

In India, the number of deaths caused yearly due to organ failure is significantly high. Only a very small percentage of people who are in need end up receiving a new organ.

To ensure that the procedure of organ transplantation goes through successfully for the small number of people who manage to get a good donor, doctors use the Tacrolimus Test frequently to decrease the odds of organ rejection after a transplant.

Other Names of Tacrolimus Test

What Does the Tacrolimus Test detect, and who is this prescribed for?

The Tacrolimus Test is useful in the following conditions:

• Monitoring the levels of Tacrolimus drug before the transplant

While preparing the body for receiving a new organ, doctors put their patients on a Tacrolimus drug regimen. This drug intake starts a few days (or weeks) before transplant surgery and makes the body less likely to reject the foreign organ.

The drug has to be kept in a specified clinical range in the body, which requires the patient to take the Tacrolimus Test regularly during that time.

• In the diagnosis of Tacrolimus Toxicity

When the levels of Tacrolimus drugs increase in the body and go beyond the therapeutic range, the condition results in Tacrolimus Toxicity. This condition has the following symptoms:

• Acute renal failure
• Headaches
• Tremors
• Electrolyte disturbances

If the healthcare professional observes any of these symptoms in the patient during the course of Tacrolimus, then they will make their patient undergo the Tacrolimus Test.

• To determine the cause of Kidney Damage

If the Tacrolimus drug level in the blood is too low, there can be kidney damage because the body will reject the transplanted organ. On the other hand, if the Tacrolimus drug level in the blood is too high, then there will be kidney damage because of Tacrolimus Toxicity.

So, if there are any signs of kidney damage, then your healthcare practitioner will ask you to undergo the Tacrolimus Test:

The Tacrolimus Test can be suggested to anyone from any age group or gender.

You can refer to the following table for interpreting your Tacrolimus Test results:

Detailed interpretation of the test results:

• If your Tacrolimus Test results fall below the range of 5.0 ng/mL or 3.0 ng/mL (according to the respective time of testing), then the chances that your body will reject the new organ on transplantation increase. On getting back these test results, your doctor may increase your Tacrolimus dosage to enhance the odds of accepting the organ.

• On the other hand, if your Tacrolimus Test results go over 15.0 ng/mL or 8.0 ng/mL, then your body may be experiencing Tacrolimus Toxicity. However, this is not a confirmation of Tacrolimus Toxicity. On the basis of your symptoms (if any in the first place), the doctor may suggest you go for further diagnostic tests to determine the underlying cause of the symptoms.

The Tacrolimus Test results can also vary depending on other factors like acute infections, medicines that can interact with the drug, genes, etc. So, you should consult with your doctor for a fitting interpretation of your Tacrolimus Test results.

The Tacrolimus Test sample is taken through blood sample collection. It is used to monitor the level of Tacrolimus drug in the blood.

How Should You Prepare for the Tacrolimus Test?

There are no preparations required for giving your Tacrolimus Test blood sample. You will not be asked to undergo fasting and can continue to drink and eat healthy food items.

If you are already taking some medications, you will have to discuss them with your healthcare practitioner and lab technician beforehand. This is because some medicines can interfere with the actual Tacrolimus Test results and thus, lead to false test results. So, your doctor may ask you to not take certain medicines right before giving your Tacrolimus Test blood sample.

The procedure of giving your blood sample for the test does not involve many risks and is usually safe. However, there can be some side effects like experiencing dizziness and weakness, excessive bleeding, etc. In such cases, you should inform the lab technician immediately.

Tacrolimus Test Parameters

The Tacrolimus test results can vary from person to person, or case to case, depending on a few factors. Some of these testing parameters include

• Kind of Transplant

For different kinds of transplants (of different organs), there can be a different clinical range for the dosage of Tacrolimus drug. The drug is mostly used only for solid organ transplants (liver, kidney, and heart). However, even within these three cases, the recommended level of Tacrolimus may vary.

• Time of Testing

The time at which the Tacrolimus Test is being conducted through a blood draw is also of importance. Medical authorities suggest undergoing the test immediately before the next dose (called the ‘trough’) and immediately following the transplant.

If the Tacrolimus Test blood sample is collected at a different time, then the level of Tacrolimus drug can vary from the therapeutic range and not give desired results.

Several other factors like genetic variability and already having some kind of acute infection can also affect the actual levels of Tacrolimus drug in the blood and give false Tacrolimus Test results.

How Frequently Should You Take the Tacrolimus Test?

The Tacrolimus Test is not part of your routine health check-up that you may be undergoing annually. The Tacrolimus Test is only recommended to people taking the Tacrolimus drug while preparing for an organ transplant surgery. Doctors can even suggest people awaiting a transplant undergo the Tacrolimus Test every day.