What should a patient's urinalysis results look like if they are taking Suboxone (buprenorphine)?

Urinalysis Results for Patients Taking Suboxone

A patient taking Suboxone (buprenorphine/naloxone) should have a positive urine test for buprenorphine and its metabolite norbuprenorphine, with both parent drug and metabolites typically appearing as glucuronide conjugates in the urine.

Expected Urinalysis Findings

Primary Components to Detect

• Buprenorphine: The parent drug
• Norbuprenorphine: The major metabolite of buprenorphine
• Glucuronide conjugates: Both buprenorphine and norbuprenorphine are extensively metabolized to their glucuronide forms

Typical Concentration Ranges

• Buprenorphine: Average of 164 ng/mL (with standard deviation of 198 ng/mL) in compliant patients 1
• Metabolite-to-parent ratio: The norbuprenorphine/buprenorphine ratio typically ranges from 0.07 to 23.0 (mean = 4.52) 1

Testing Considerations

Detection Methods

1. Immunoassay screening:

   • Initial screening method
   • Using a 5 ng/mL cutoff, the sensitivity is 100% and specificity is 87.5% compared to LC-MS/MS 1

2. Confirmatory testing:

   • LC-MS/MS (liquid chromatography-tandem mass spectrometry) is the gold standard for confirmation
   • Directly quantitates buprenorphine, norbuprenorphine, their glucuronide conjugates, and naloxone 2

Important Testing Factors

• Hydrolysis step: Often required to break down glucuronide conjugates for complete detection
• Matrix selection: Urine is superior to oral fluid for detecting buprenorphine compliance (97% vs 78% detection in prescribed patients) 3
• Conjugation variability: The extent of conjugation in urine is highly variable, with unconjugated buprenorphine averaging 6.4% and norbuprenorphine averaging 34% of total drug 4

Red Flags in Urinalysis Results

Potential Signs of Non-Compliance

• Absence of buprenorphine: Approximately 15.3% of samples from patients on Suboxone may have no detectable buprenorphine 1
• Low metabolite-to-parent ratio: Ratios < 0.02 (found in 4.2% of samples) may indicate sample adulteration 1
• Diluted samples: Creatinine < 20 mg/dL (found in 16.7% of samples) suggests potential dilution 1

Sample Adulteration

• Direct quantitation of glucuronide conjugates can help distinguish genuine compliance from specimen adulteration intended to mimic compliance 2
• Approximately 7.3% of samples may show evidence of adulteration 1

Clinical Implications

Monitoring Recommendations

• Baseline urine drug testing should be performed before initiating therapy 5
• Regular monitoring with urine drug testing is essential for ongoing assessment 5
• Consider specialized testing methods when standard assays are insufficient 5

Interpreting Results

• Unexpected results should prompt a conversation with the patient rather than immediate punitive action 5
• Consider timing of medication administration relative to testing 5
• Document all current medications to help interpret results accurately 5

Caution

• Never dismiss patients from care based solely on urine drug test results 5
• Standard opiate screens may not detect buprenorphine - specific testing is required 6
• False positives can occur with certain medications and substances 5

By understanding these expected patterns in urinalysis, clinicians can better monitor treatment adherence and identify potential misuse or diversion of Suboxone.