Clinicians' Frequently Asked Questions

What is Pharmacogenetics testing?

Pharmacogenetics testing is the testing of certain genes to determine how individuals are going to react to specific medications. This greatly decreases the need for "trial and error" dosing and can substantially reduce the risk of Adverse Drug Reactions (ADRs).

Pharmacogenetics testing is a very new tool in medicine. It's just being introduced to many physicians, hospitals and clinics. Pharmacogenetics is a science that holds enormous promise, and will doubtless reduce medical costs and increase the effectiveness of many drugs in the future.

How well established is the science of Pharmacogenetics?

The science of pharmacogenetics is both well established and rapidly changing. There is no doubt that specific genes influence how individuals react to medications. The genes have in most cases been identified, and variations in these genes have been tracked. The effect these variations have on specific medications is, in some cases, less well-established. For some drugs the effects are well documented and indicate specific changes in dosages. For others, therapeutic changes are not as well documented.

Read more about the development of pharmacogenetics.

Browse additional research on pharmacogenetics testing.

Brose the list of drugs that have been fully researched.

To what drugs does Pharmacogenetics testing apply?

The effect of genetic variations on specific medications is well documented for some drugs, and less well documented for others. In general, drugs with a very narrow effective dosing range have been researched, while drugs with a wide effective range have not.

Browse the list of drugs for which research strongly indicates the efficacy of pharmacogenetics testing.

When is Pharmacogenetics testing indicated?

Pharmacogenetics tests are indicated primarily when a patient embarks on long-term therapy using a drug that has a narrow therapeutic index. A perfect example is coumadin (Warfarin). Therapy can last for years; the effective range is very narrow; and dosing that wanders out of the safe and effective range can have severe consequences. There is little doubt that all patients embarking on long-term coumadin therapy should be tested.

The answer for other drugs is not so clear-cut, although an emerging body of evidence suggests that those embarking on even relatively low-risk drug regimens would benefit from pharmacogenetics testing, since it would enable their physicians to anticipate differences in dose requirement, increased difficulty with drug interactions, and the likelihood that the drug will be therapeutically effective.

Browse additional research on pharmacogenetics testing.

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Where do I find additional research on pharmacogenetics?

We've assembled a small library of links for physicians, pharmacists, researchers, and others interested in the science underlying pharmacogenetics testing.

How much do Pharmacogenetics tests cost?

On our website, you can view our test menu, quick reference guide (pdf) and our test packet (pdf), complete with information for ordering and sample collection.

Please contact us for information about discounts for research, clinical trials and multiple-test orders.

How do I order a Pharmacogenetics test for a patient?

It's easy. First, you need to make sure the medication you're interested in is on our drug list. Also see our quick reference guide (pdf) for at-a-glance information regarding drugs that are known to be affected by the Cytochrome P450 genes, and for which dosage adjustments have been researched.

Next, you need to fill out an order form, collect a blood sample, and send it to us. We run the test as soon as the sample arrives at our lab, and results can be reported to you either by e-mail or surface mail. You make the choice when you fill out your order form. Our test packet (pdf) will walk you through the process.

If you have any questions, or if you'd just like to talk with us before ordering a test, please feel free to contact us.

What are PGXL Laboratories' Qualifications?

PGXL Laboratories is a CLIA-certified testing facility that performs pharmacogenetics testing for purposes of optimizing patient care. Our tests are designed to identify known variant alleles, primarily of drug metabolizing enzymes which are known to alter the pharmacokinetics of medications, changing the maintenance dose required to establish desired therapeutic results.

Learn more about PGXL Laboratories.

How do I interpret the test results?

PGXL Laboratories returns the test to you along with information on what the test results imply about drug dosing. You can also view interpretive guidelines on our website. We'll keep the guidelines updated as new research comes in. For more information, we have also gathered a collection of links to pharmacogenetics research.

Drug manufacturers are increasingly including pharmacogenetics data in the package information included with drugs. Pharmacists are also a good source of information.

If you have any questions, please contact us.