Specimen Collection and Laboratory Procedures

A defensible drug-test result depends on the entire process—not only the instrument used by the laboratory. Identity checks, collection conditions, tamper-evident seals, custody documentation, specimen transport, analytical controls, confirmation, medical review, and secure reporting all affect reliability.

This hub explains each stage and links to detailed guides. Return to Drug Testing: The Complete Guide for the full subject.

The testing pathway

  1. Order and authority: the requesting party defines the purpose, specimen, panel, cutoff, and governing rules.
  2. Collection: a trained collector verifies identity, explains the procedure, secures the site, obtains the specimen, and completes required records.
  3. Transport and accessioning: sealed specimens are transferred to the laboratory, which checks identifiers, seals, quantity, and condition.
  4. Initial testing: the laboratory applies a validated screening method and cutoff.
  5. Confirmation: a different analytical procedure identifies and measures a specific drug or metabolite in a separate portion of the specimen.
  6. Medical review: when the program provides for it, an MRO evaluates confirmed nonnegative results and legitimate medical explanations.
  7. Reporting and retention: authorized results and records are transmitted, secured, retained, and eventually destroyed under the applicable rules.

Collection is more than providing a specimen

The collector protects privacy while preserving integrity. Procedures vary by specimen and program. Federal urine and oral-fluid collections use specific materials, forms, split-specimen procedures, and security steps. A directly observed collection is permitted only under defined circumstances. Learn more in What Happens During a Drug-Test Collection?.

Chain of custody

Chain of custody documents who handled the specimen, when control changed, and whether seals and identifiers remained intact. The federal Custody and Control Form connects the donor, collector, specimen bottles, delivery service, laboratory, and MRO. Nonregulated programs may use different forms, but the same accountability principle applies. See Drug-Testing Chain of Custody Explained.

Screening and confirmation

An initial screen efficiently separates specimens below the cutoff from those requiring additional analysis. A screen-reactive or presumptive-positive result is not a final confirmed result. Confirmation uses a more specific analytical method to identify and quantify the target analyte. Read How Laboratories Confirm Results.

Specimen validity

Urine validity testing can identify dilution, substitution, adulteration, or an invalid specimen. These are technical categories with defined criteria in regulated programs; they should not be inferred from appearance alone. A validity result is distinct from the drug result, although it may determine whether another collection is required.

The Medical Review Officer

A qualified MRO is an independent physician reviewer in federal and many workplace programs. The MRO checks laboratory information, interviews the donor when required, evaluates legitimate medical explanations, protects unnecessary medical detail, and reports a verified result to the authorized party. Explore The Role of the Medical Review Officer.

Laboratory quality

Certification or accreditation is program-specific. DOT and federal workplace specimens must go to laboratories certified by HHS for the applicable methodology. Clinical testing for diagnosis or treatment generally falls under CLIA. Accreditation, proficiency testing, method validation, calibration, quality controls, staff competency, audits, and corrective action work together; no single badge guarantees that every offered test is appropriate. See Laboratory Accreditation and Quality Control.

Questions to ask a testing provider

  • Which rule or clinical standard governs this test?
  • Is the laboratory certified or accredited for this specimen and method?
  • What are the screen and confirmation cutoffs?
  • How are identity, seals, transport, and chain of custody documented?
  • Who reviews nonnegative results and medication explanations?
  • How can the donor request records, split-specimen testing, or correction of an error?

Sources

Scientific and regulatory review: October 29, 2026.