Open Access Open Access  Restricted Access Subscription or Fee Access

Interpretation of oxycodone concentrations in oral fluid

Christine Moore, PhD, Tara Kelley-Baker, PhD, John Lacey, MPH


Objective: The purpose of this retrospective study was to compare oxycodone concentrations in saliva and whole blood with a view to propose therapeutic concentrations in oral fluid. Oral fluid is an easy specimen to collect with several advantages over urine, including ease of collection and difficulty of adulteration. As oral fluid is a reflection of free drug circulating in the blood, drug concentrations in saliva are more closely related to blood levels than urine concentrations. The number of testing laboratories offering the analysis of prescription pain medications in urine has increased significantly over the last few years, along with the overuse and abuse of pain killing drugs, specifically oxycodone. Hence, the utility of oral fluid analysis in this field was assessed.

Design: Paired specimens of blood and oral fluid were retrospectively studied in an attempt to establish a range for oxycodone concentrations in oral fluid reflective of therapeutic intake. Twenty-three paired oral fluid—blood specimens were studied. Oral fluid samples had been collected with the Quantisaloral fluid device, stored cold and shipped overnight to the laboratory prior to testing. Blood specimens were collected simultaneously in gray top tubes.

Results: From 23 pairs of samples, the median concentration in oral fluid was 524 µg/L and blood was 53 µg/L. The whole blood to plasma ratio for oxycodone was 1.3, so the median plasma concentration was 41 µg/L projecting a saliva to plasma ratio (S:P ratio) of 12. The comparison of oral fluid—blood concentrations allowed the projection of a S:P ratio for oxycodone and the development of a potential therapeutic range for oxycodone in oral fluid.

Conclusion: Saliva drug concentrations in pain management are more closely related to blood levels than urine so can be more easily interpreted. These data provide a foundation for interpretative advances; however, further research surrounding other pain medications and controlled studies are necessary.


oral fluid, oxycodone, interpretation of drug concentrations

Full Text:



Walsh SL, Nuzzo PA, Lofwall MR, et al.: The relative abuse liability of oral oxycodone, hydrocodone and hydromorphone assessed in prescription opioid abusers. Drug Alcohol Depend. 2008; 98(3): 191-202.

Aquina CT, Marques-Baptista A, Bridgeman P, et al.: OxyContin abuse and overdose. Postgrad Med. 2009; 121(2): 162-167.

Toennes SW, Kauert GF, Steinmeyer S, et al.: Driving under the influence of drugs–evaluation of analytical data of drugs in oral fluid, serum and urine, and correlation with impairment symptoms. Forensic Sci Int. 2005; 152: 149-155.

Reisfield GM, Salazar E, Bertholf RL: Rational use and interpretation of urine drug testing in chronic opioid therapy. Ann Clin Lab Sci. 2007; 37(4): 301-314.

Cone EJ, Caplan YH: Urine toxicology testing in chronic pain management. Postgrad Med. 2009; 121(4): 91-102.

Nafziger AN, Bertino JS: Utility and application of urine drug testing in chronic pain management with opioids. Clin J Pain. 2009; 25(1): 73-79.

Mullangi R, Agrawal S, Srinivas NR: Measurement of xenobiotics in saliva: is saliva an attractive alternative matrix? Case studies and analytical perspectives. Biomed Chromatogr. 2009; 23(1): 3-25.

Drummer OH: Drug testing in oral fluid. Clin Biochem. 2006; 27: 147-159.

Cone EJ, Huestis MA: Interpretation of oral fluid tests for drugs of abuse. Ann N Y Acad Sci.2007; 1098: 51-103.

Baselt RC: Disposition of Toxic Drugs and Chemicals in Man. 8th ed. Foster City: Biomedical Publications, 2008.

Winek CL, Wahba WW, Winek CL Jr: Drug and chemical blood level data 2001. Forensic Sci Int. 2001; 122(2-3): 107-123.

Couto JE, Romney MC, Leider HL, et al.: High rates of inappropriate drug use in the chronic pain population. Popul Health Manag. 2009; 12(4): 185-190.

Bermejo AM, Lucas ACS, Tabernero MJ: Saliva/plasma ratio of methadone and EDDP. J Anal Toxicol. 2000; 24: 70-71.

Rana S, Moore C, Vincent M, et al.: Determination of propoxyphene in oral fluid, J Anal Toxicol. 2006; 30(8): 516-518.

Wille SM, Lillsunde P, Gunnar T, et al.: Relationship between oral fluid and blood concentrations of drugs of abuse in drivers suspected of driving under the influence of drugs. Ther Drug Monit. 2009; 31(4): 511-519.

Moore C, Rana S, Coulter C: Determination of meperidine, tramadol and oxycodone in human oral fluid using solid phase extraction and gas chromatography-mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci. 2007; 850: 370-375.

Ritschel WA, Parab PV, Denson DD, et al.: Absolute bioavailability of hydromorphone after peroral and rectal administration in humans: saliva/plasma ratio and clinical effects. J Clin Pharmacol. 1987; 27: 647-653.

Ruiz ME, Conforty P, Fagiolini P, et al.: The use of saliva as a biological fluid in relative bioavailability studies: comparison and correlation with plasma results. Biopharm Drug Dispos. 2010; 31: 476-485.

Hardy J, Norris R, Anderson H, et al.: Is saliva a valid substitute for plasma in pharmacokinetic studies of oxycodone and its metabolites in patients with cancer? Support Care Cancer. 2011 (in press). doi:10.1007/s00520-011-1147-3.

Collins A, Bourland J, Backer R: Disposition of oxycodone in oral fluid. Presented at the Proceedings of the 39th Annual SOFT Conference, Oklahoma City, OK, 2009. Poster #8.



  • There are currently no refbacks.