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Test Code LAB1230481 Clomipramine, Serum

Important Note

May 8, 2018 - This test replaces LAB752

Additional Codes

Mayo Code: CLOM

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Determining whether a poor therapeutic response is attributable to noncompliance


Monitoring serum concentration of clomipramine and norclomipramine to assist in optimizing the administered dose

Reporting Name

Clomipramine, S

Specimen Type

Serum Red

Specimen Required

Container/Tube: Red top

Specimen Volume: 1 mL

Collection Instructions:

1. Draw specimen immediately before next scheduled dose (minimum 12 hours after last dose).

2. Serum must be separated from cells within 2 hours of draw.

Specimen Minimum Volume


Specimen Stability Information

Specimen Type Temperature Time
Serum Red Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  7 days

Reject Due To


Mild OK; Gross OK


Mild OK; Gross OK


Mild OK; Gross OK


Serum gel tube

Clinical Information

Clomipramine (chlorimipramine, Anafranil) is a tricyclic antidepressant drug used primarily to treat obsessive-compulsive disorder (OCD). Clomipramine is also used to treat panic disorder and treatment-resistant depression.


Clomipramine preferentially blocks synaptic reuptake of serotonin; its pharmacologically active metabolite, norclomipramine (desmethylchlorimipramine) preferentially blocks synaptic reuptake of norepinephrine.


Clomipramine undergoes significant first-pass hepatic metabolism (up to 50%) which probably explains the high degree of interindividual variability observed between administered dose and steady-state serum concentrations of the drug and its metabolite. The serum ratio of clomipramine to norclomipramine is typically 1:2-2.5. The elimination half-lives of clomipramine and norclomipramine are 19-37 hours and 54-77 hours, respectively. One to two weeks are required to achieve steady-state when a patient is started on clomipramine or following an alteration in the dose.


Anticholinergic side effects (ie, dry mouth, excessive sweating, blurred vision, urinary retention, constipation) frequently accompany treatment. Other side effects may include tremor, nausea, orthostatic hypotension, dizziness, sexual dysfunction, and sleep disturbances. Signs and symptoms following overdose are similar to other tricyclic antidepressant drugs: cardiac toxicity (eg, tachycardia, arrhythmia, impaired conduction, congestive heart failure) is the major concern.

Reference Values


Therapeutic concentration: 230-450 ng/mL


Note: Therapeutic ranges are for specimens drawn at trough (ie, immediately before next scheduled dose). Levels may be elevated in non-trough specimens.


Studies investigating the relationship between serum concentrations of clomipramine and norclomipramine and therapeutic response have yielded conflicting results. However, the probability of therapeutic failure seems to increase if the sum of the clomipramine and norclomipramine serum concentrations is <230 ng/mL. Summed serum concentrations of clomipramine and norclomipramine which exceed 450 ng/mL seem to result in no additional enhancement in therapeutic response and may predispose the patient to greater risk of adverse side affects. A toxic range has not been well established at this time.

Clinical Reference

1. Wille SM, Cooreman SG, Neels HM, Lambert WE: Relevant issues in the monitoring and the toxicology of antidepressants. Crit Rev Clin Lab Sci 2008;45(1):25-89

2. Thanacoody HK, Thomas SH: Antidepressant poisoning. Clin Med 2003;3(2):114-118

3. Hiemke C, AGNP Concensus Guidelines for Therapeutic Drug Monitoring in Psychiatry: Update 2011. Pharmacopsychiatry 2011;44(6):195-235

4. Burtis CA, Ashwood ER, Bruns DE. (2012) Tietz Textbook of Clinical Chemistry and Molecular Diagnostics: Fifth Edition, Elsevier

Method Description

The tricyclic antidepressants are extracted from serum using a solvent crash to precipitate proteins. The supernatant is remove and analysis is by LC-MS/MS.(Unpublished Mayo method)

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Day(s) and Time(s) Performed

Monday through Friday; Varies

Analytic Time

2 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CLOM Clomipramine, S 43127-0


Result ID Test Result Name Result LOINC Value
80902 Clomipramine 3491-8
7983 Norclomipramine 3536-0
7984 Clomipramine + Norclomipramine 3493-4

CPT Code Information


G0480 (if appropriate)