Citalopram Drug Level
Label Mnemonic: CELEXA
Epic Lab Code: LAB2870
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Serum
Collection Medium:
Red top tube 5 mL (Clot Activator)
Minimum:
0.5 mL serum in a plain, red-tope tube
Rejection Criteria:
Gel separator tubes
Delivery Instructions:
Deliver to laboratory immediately after collection.
Turn Around Time:
1-3 days upon receipt at reference laboratory.
Reference Range:
50-110 ng/mL
Interpretive Data:
Steady-state serum concentrations associated with optimal response to citalopram are in the range of 50 to 100 ng/mL when the patient is administered the R,S-enantiomeric mixture (Celexa).

The most common toxicities associated with excessive serum concentration are fatigue, impotence, insomnia, and anticholinergic effects. The toxic range for citalopram is >220 ng/mL.
Comments:
Useful For:
Monitoring citalopram therapy.

Identifying noncompliance, although regular blood level monitoring is not indicated in most patients.

Identifying states of altered drug metabolism when used in conjunction with CYP2C19 and CYP3A4-5 genotyping.

Cautions:
Test interpretation requires knowledge of which enantiomers (R, S-
or S-) are prescribed; this assay does not distinguish the 
enantiomers.
Test Limitations:
Steady-state serum concentrations associated with optimal response to citalopram are in the range of 100 to 250 ng/mL when the patient is administered the R,S-enantiomeric mixture (Celexa) and 50 to 130 ng/mL when S-citalopram (Lexapro) is administered.

The most common toxicities associated with excessive serum concentration are fatigue, impotence, insomnia, and anticholinergic effects. The toxic range for R,S-citalopram is >400 ng/mL and S- citalopram is >250 ng/mL.
Methodology:
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
CPT Code:
80332
 
See Additional Information:
Specimens Requiring Immediate Delivery