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Blood testing provides pivotal information pertaining to how a medication is being taken

In compliance testing, the inability to correlate urine drug concentrations with a dose of prescribed medication has become a common frustration for healthcare providers. Certain patients choose to divert some of their medication or obtain additional prescriptions from multiple providers. As long as such patients have taken a dose of their prescription medication in recent days, their urine will likely test positive for the appropriate drug and/or metabolite.

Blood testing in combination with urine drug testing can provide a more complete picture of patient compliance. 

Limitations of Urinalysis for Compliance Testing 
Benefits of Blood Analysis for Compliance Testing
Significance of Steady-State Blood Concentrations in Postmortem Investigations
Your Partner in Compliance Testing 

Limitations of Urinalysis for Compliance Testing 

Urine drug testing remains the mainstay for identifying illicit or non-prescribed drug use for many reasons and is ideal for establishing recent drug exposure. Urine drug concentrations are typically much higher than those in corresponding blood (serum) samples and consequently allow a longer window of detection than blood. However, urine toxicology results cannot provide evidence of therapeutic effect and cannot be used to estimate dose. Multiple variables associated with drug disposition in the body induce highly variable drug-metabolite concentrations from a given dose. Variables include:

• Pharmacogenetics
• Metabolism
• Absorption and elimination rates
• Urinary pH
• State of hydration
• Drug formulation and co-administered medications

Simply put, the presence of a drug in the urine only indicates use in recent days. So although a patient may test positive for a prescribed medication, a urine drug test result cannot tell the physician if the patient has been taking more or less than prescribed.

Benefits of Blood Analysis for Compliance Testing 

Routine blood testing provides the physician with a documented steady-state blood concentration – a crucial piece of information for moderate- to high-dose opioid patients that can not only protect the prescriber but also patients and their families.

The theoretical application of blood analysis for compliance testing is simple:

• Patients taking daily doses of opioids for the treatment of pain should have steady-state blood concentrations that reflect the ingested dose
• Patients taking infrequent doses in order to pass a urine drug test will have blood concentrations below their expected steady-state range
• Patients obtaining additional medication and taking more than prescribed will have blood concentrations above their expected steady-state range

Detection windows for certain drugs in blood may be as short as a few to several hours; this necessitates the use of urine testing in conjunction with blood testing for the most complete picture of patient compliance.

Significance of Steady-State Blood Concentrations in Postmortem Investigations 

In the case of tolerant pain patients, routine blood testing to determine steady-state blood ranges may provide crucial information in the event of a patient’s unexpected death. Tolerant pain patients are often able to function with opioid blood concentrations well above what is considered “therapeutic,” “toxic,” or even “lethal” in naïve, non-tolerant patients. To compare therapeutic and toxic blood levels, see the chart below.

 
Unfortunately, the issue of tolerance may not always be considered in postmortem investigations, and elevated concentrations of opioids in postmortem specimens can be misleading when evaluating the cause of death. Periodic blood draws on all opioid patients for the purpose of documenting tolerance could help to protect physicians from possible investigation in the unfortunate event of a patient’s death.

Your Partner in Compliance Testing 

When it comes to prescription drug monitoring and narcotics testing, AIT was one of the first toxicology laboratories in the country to develop a testing program customized for healthcare providers monitoring patient compliance. We are ready to partner with you to verify compliance, identify potential drug misuse and diversion quickly, and help you make objective, informed decisions regarding patient care.

To learn more about our compliance testing services, click here. 

To read about our premiere prescription drug testing and narcotics panel, DetectiMed®, click here. 

For more information about AIT’s blood testing services for compliance testing, contact our Client Services Department.