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Paediatric Laboratory Medicine

Tricyclic Screen, Serum or Plasma (B)

Clinical Significance

Amitriptyline, imipramine and related compounds comprise the tricyclic antidepressants. They are widely used for the treatment of depression, chronic pain and enuresis. Therapeutic serum concentrations and toxic levels are different for each tricyclic drug. Screening assays such as this are used to establish the presence or absence of the drug class based on a pre-determined threshold value. Alternative methods must be employed to determine the identity and concentration of any tricyclic from a positive screening result. Toxicity symptoms include: tachycardia, orthostatic hypotension, dry mouth, dilated pupils, hyperthermia, seizures, ataxia and delerium.

Test Name

Tricyclic Screen, Serum or Plasma (B)

Alternate Name/ Synonym

Amitriptylline, Nortriptylline, Imipramine

Test Code


Drug Class

Psychotropic Drugs





External Proficiency Testing


Turn Around Time

Daily, Stat

Specimen Type

Serum, Plasma (Heparin, Citrate or EDTA)

Minimum Specimen Requirements

500 uL


4°C (transport with a cool pack if possible)

Approval is not required

CPT Codes


Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Phone: 416-813-7200
Phone: 1-855-381-3212

Therapeutic Range

Not detected

Critical Values

Not Detected: < 25 ug/L
Positive:  > 26 ug/L