Analysis of alternative matrices

In forensic toxicology, analysis of whole blood represents the “gold standard” as concentrations in this medium allows for evaluation of influence and intoxication. In cases where drug use is the issue, e.g. for the prison and probation services, urine is the standard medium. In some cases other matrices can be a better choice. Oral fluid can be sampled under surveillance without the invasion of privacy needed for urine sampling, and hair can uncover long term use of drugs. Dried blood spots is another alternative for less invasive sample collection. In autopsy cases where whole blood is not available due to e.g. severe blood loss or burns, matrices such as pericardial fluid, muscle or vitreous humour could be alternatives. In special cases, stomach content or faeces can be other alternative matrices.

©Division of Forensic Sciences, Oslo University Hospital

Figure 1. Hair sampling (left panel), dried blood samples collected with volumetric absorptive microsampling, VAMS (middle panel), oral fluid sampling (right panel). ©Division of Forensic Sciences, Oslo University Hospital

Ongoing projects

Sensitivity of the metabolite THC-acid in hair as a biomarker to detect chronic cannabis use

THC-acid (THC-COOH) is reported to be the only hair marker that can distinguish between active consumption and passive exposure to cannabis. There is limited knowledge about the relation between extent of use and THC-COOH concentrations. In this study, we investigate the sensitivity of THC-COOH in hair to detect chronic cannabis use, and the quantitative relation between THC-COOH concentrations and self-reported extent of use. The study is performed in collaboration with three substance abuse institutions in Oslo (Agency for Social and Welfare Services). Currently, the analyses are complete, and data processing is in progress.

Analysis of dried matrix samples

Dried samples collected on filterpaper, in polymer materials or other devices can provide alternatives in cases where collection of ordinary samples is difficult. We have in later years

  • tested volumetric absorptive micro samplers (VAMS) for drugs of abuse and for samples from research animal
  • used filter paper as an inexpensive way of sampling in a proof-of-principle study together with partners in Cameroon
  • analysed oral fluid from used Drugwipe on-site tests to compare with whole blood samples and immuno assay results from the on-site tests

Several of the projects are performed together with the group for Substance Use and Health Outcomes or the group for Experimental Drug Abuse Research.

Development of a UHPLC-MS/MS method for determination of GHB in oral fluid

In collaboration with the hospitals Acute Medicines Research Group and our department’s research group for Substance Use and Health Outcomes, we have developed a method for analysis of GHB in oral fluid. Although a few other methods for analysis of GHB in oral fluid exist, this is to our knowledge the first high throughput method developed. In addition to GHB the method includes the GHB precursors GBL and 1,4 DB as well as the medicinal drug pregabaline.

Past projects

Analysis of rodenticides in faeces

The project has been a collaboration with the Poison information Centre and the Veterinary Institute, to use faeces as an alternative matrix to evaluate rodenticide exposure.

Oral fluid analysis and comparison to other media

Several methods for analysis of drugs of abuse in oral fluid have been developed, and comparison of detection times found for oral fluid and whole blood or urine has been performed. 

Development of methods for hair analysis

Methods for analysis of drugs of abuse and the alcohol metabolite EtG using UHPLC-MS/MS have been developed, as well as a GC-MS/MS method for THC-acid. An ongoing project studies THC-acid use for chronical users. 


Yannick Oyono,
(PhD candidate) Faculty of Health Sciences, University of Buea, Buea, Cameroon
Stig Pedersen-Bjerregaard,
Department of Pharmacy, University of Oslo, Oslo, Norway
Marilyn Huestis,
Institute of Emerging Health Professions, Thomas Jefferson University, Philadelphia, USA

If you have questions about the projects or suggestions for research collaboration, please contact: Elisabeth Leere Øiestad (


Gjerde H, Oyono Y, Jamt REG, Tayimetha CY, Asongalem EA, Akum EA, Øiestad EL (2023)
Drug analysis: Comparison between dried plasma spots and liquid plasma samples of trauma patients from Cameroon-A feasibility study
Drug Test Anal
DOI 10.1002/dta.3545, PubMed 37464568 

Øiestad EL, Øiestad ÅML, Middelkoop G, Brochmann GW, Thaulow CH, Vindenes V (2023)
Comparative Study of Postmortem Concentrations of Benzodiazepines and Z-Hypnotics in Several Different Matrices
J Anal Toxicol, 47 (3), 287-298
DOI 10.1093/jat/bkac106, PubMed 36542823

Mestad IO, Gjelstad A, Pedersen-Bjergaard S, Oiestad EL (2021)
Green and sustainable drug analysis-Combining microsampling and microextraction of drugs of abuse
Sustain, Chem. Pharm, 24, 100517
DOI 10.1016/j.scp.2021.100517

Pettersen S, Øiestad ÅML, Rogde S, Brochmann GW, Øiestad EL, Vindenes V (2021)
Distribution of tetrahydrocannabinol and cannabidiol in several different postmortem matrices
Forensic Sci Int, 329, 111082
DOI 10.1016/j.forsciint.2021.111082, PubMed 34775328

Bakke E, Høiseth G, Furuhaugen H, Berg T, Arnestad M, Gjerde H (2020)
Oral Fluid to Blood Concentration Ratios of Different Psychoactive Drugs in Samples from Suspected Drugged Drivers
Ther Drug Monit, 42 (5), 795-800
DOI 10.1097/FTD.0000000000000760, PubMed 32251151

Seljetun KO, Sandvik M, Vindenes V, Eliassen E, Øiestad EL, Madslien K, Moe L (2020)
Comparison of anticoagulant rodenticide concentrations in liver and feces from apparently healthy red foxes
J Vet Diagn Invest, 32 (4), 560-564
DOI 10.1177/1040638720927365, PubMed 32476615

Seljetun KO, Vindenes V, Øiestad EL, Brochmann GW, Eliassen E, Moe L (2020)
Determination of anticoagulant rodenticides in faeces of exposed dogs and in a healthy dog population
Acta Vet Scand, 62 (1), 30
DOI 10.1186/s13028-020-00531-5, PubMed 32546243

Bakke E, Høiseth G, Arnestad M, Gjerde H (2019)
Detection of Drugs in Simultaneously Collected Samples of Oral Fluid and Blood
J Anal Toxicol, 43 (3), 228-232
DOI 10.1093/jat/bky079, PubMed 30295809

Oiestad EL, Krabseth HM, Huestis MA, Skulberg A, Vindenes V (2019)
Interpreting oral fluid drug results in prisoners: monitoring current drug intake and detection times for drugs self-administered prior to detention
Forensic Toxicol., 37 (1), 59-74
DOI 10.1007/s11419-018-0434-9

Seljetun KO, Eliassen E, Madslien K, Viljugrein H, Vindenes V, Øiestad EL, Moe L (2019)
Prevalence of Anticoagulant Rodenticides in Feces of Wild Red Foxes (Vulpes Vulpes) in Norway Prevalence of anticoagulant rodenticides in feces of wild red foxes (vulpes vulpes) in Norway.
J Wildl Dis, 55 (4), 834-843
DOI 10.7589/2019-01-027, PubMed 31112468

Bruun LD, Kjeldstadli K, Temte V, Birdal M, Bachs L, Langødegård M, Strand DH, Gaare KI, Øiestad E, Høiseth G (2019)
Detection Time of Oxazepam and Zopiclone in Urine and Oral Fluid after Experimental Oral Dosing
J Anal Toxicol, 43 (5), 369-377
DOI 10.1093/jat/bky083, PubMed 30615130

Strand MC, Ramaekers JG, Gjerde H, Mørland J, Vindenes V (2019)
Pharmacokinetics of Single Doses of Methadone and Buprenorphine in Blood and Oral Fluid in Healthy Volunteers and Correlation With Effects on Psychomotor and Cognitive Functions
J Clin Psychopharmacol, 39 (5), 489-493
DOI 10.1097/JCP.0000000000001077, PubMed 31305338

Temte V, Kjeldstadli K, Bruun LD, Birdal M, Bachs L, Karinen R, Middelkoop G, Øiestad E, Høiseth G (2019)
An Experimental Study of Diazepam and Alprazolam Kinetics in Urine and Oral Fluid Following Single Oral Doses
J Anal Toxicol, 43 (2), 104-111
DOI 10.1093/jat/bky062, PubMed 30517712

Høiseth G, Arnestad M, Karinen R, Morini L, Rogde S, Sempio C, Vindenes V, Øiestad ÅML (2018)
Is Hair Analysis Useful in Postmortem Cases?
J Anal Toxicol, 42 (1), 49-54
DOI 10.1093/jat/bkx077, PubMed 28977558

Øiestad ÅML, Karinen R, Rogde S, Nilsen S, Boye Eldor KB, Brochmann GW, Arnestad M, Øiestad EL, Peres MD, Kristoffersen L, Vindenes V (2018)
Comparative Study of Postmortem Concentrations of Antidepressants in Several Different Matrices
J Anal Toxicol, 42 (7), 446-458
DOI 10.1093/jat/bky030, PubMed 29762694

Seljetun KO, Eliassen E, Karinen R, Moe L, Vindenes V (2018)
Quantitative method for analysis of six anticoagulant rodenticides in faeces, applied in a case with repeated samples from a dog
Acta Vet Scand, 60 (1), 3
DOI 10.1186/s13028-018-0357-9, PubMed 29343296

Thaulow CH, Øiestad ÅML, Rogde S, Andersen JM, Høiseth G, Handal M, Mørland J, Vindenes V (2018)
Can measurements of heroin metabolites in post-mortem matrices other than peripheral blood indicate if death was rapid or delayed?
Forensic Sci Int, 290, 121-128
DOI 10.1016/j.forsciint.2018.06.041, PubMed 30015276

Ask KS, Øiestad EL, Pedersen-Bjergaard S, Gjelstad A (2018)
Dried blood spots and parallel artificial liquid membrane extraction-A simple combination of microsampling and microextraction
Anal Chim Acta, 1009, 56-64
DOI 10.1016/j.aca.2018.01.024, PubMed 29422132

Fosen JT, Morini L, Sempio C, Giarratana N, Enger A, Mørland J, Høiseth G (2017)
Ethyl Glucuronide Elimination Kinetics in Fingernails and Comparison to Levels in Hair
Alcohol Alcohol, 52 (5), 580-586
DOI 10.1093/alcalc/agx035, PubMed 28591773

Jan 25, 2024 Page visits: 1039