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 Toxicology Services

Marshfield Labs is proud to offer a large test menu to support testing to meet the needs of a variety of specialties, including:

  • Pain Management and compliance testing
  • In-patient or out-patient drug treatment facilities
  • Juvenile group home patient monitoring
  • Therapeutic drug monitoring (limited serum test menu, including monitoring of immunosuppressant drugs Tacrolimus and Cyclosporine)
  • Medically necessary testing (pre-surgery, toxicity/overdose cases, etc.)

Test Options

There are numerous testing options that can be tailored to meet the needs of the clinician:
  • "Screen Only" tests, which use immunoassay testing of drug classes. The benefits of this test are low cost, and fast results. These tests are best suited for use by clinicians who feel comfortable interpreting toxicology results.
  • "Confirm Only" tests which quantitate individual drugs within each drug class. This test is best suited for targeted testing, in which only specific drug class(es) are of interest.
  • "Panel Tests" are the best option for the general population. These tests include immunoassay screening with automatic reflexing to confirmatory tests when needed. Also included in each panel is Specimen Validity testing (SVT) to insure that the sample has not been tampered with (adulterated) or substituted.

Quantitative Confirmatory Testing

The Toxicology Laboratory uses GC, GC/MS, LC/MS/MS or LC/MS-QToF methodologies to identify and definitively confirm medications and drugs of abuse. This testing is extremely sensitive and reliable.

See the "Current Cutoff Levels for Toxicology Testing" document for information on detection limits.

Specimen Validity Testing

The Toxicology Laboratory uses a multi-step process to help insure the reliability of the drug test results. If a sample does not meet the criteria to rule-out tampering of the sample, the report includes information to alert the clinician of possible dilution, substitution, or adulteration.
  • Validity testing is included in all panels, and consists testing for creatinine, pH, and oxidizing adulterants. Validity testing insures that results are reliable, and is included for no extra cost.
  • Additionally, Marshfield Labs will provide all the supplies necessary to collect the samples, including a collection cup with a temperature strip as an extra step to help insure that the sample is valid. If the temperature is out-of-range, this will be indicated on the report. Please call a Marshfield Labs Client Services representative to request supplies.


Previously a SAMHSA and CAP Forensic Toxicology certified laboratory, we still adhere to forensic guidelines whenever possible. We are currently CLIA and CAP certified. Marshfield Labs maintains a vigorous Proficiency Testing Program to ensure accuracy.

 Toxicology Laboratory

Directed by Dr. Joyce Flanagan

Phone: 800-331-3734

​​Current Cutoff Levels for Toxicology Testing

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