Test Overview
Test Methodology

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

Test Usage

Monitor therapeutic drug level.

Reference Range *

Trimethoprim: >2.0 mcg/mL; Sulfamethoxazole: >50 mcg/mL

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Days Set Up
=Monday, Thursday
Analytic Time

2 - 7 days

Soft Order Code
  • Trimethoprim
  • Sulfamethoxazole
  • CO-Trimoxazone
  • Cotrimoxazole
  • Septra
  • Bactrim
Reference Laboratory
Mayo TMP (80146) Trimethoprim, SFZ (8238) Sulfamethoxazole
Special Testing
Specimen Requirements
Collection Instructions

Collect specimen in a red top tube; do not use SST tube. Centrifuge, aliquot serum into a plastic vial, and freeze within 2 hours of collection.

Normal Volume
1 mL serum
Minimum Volume
0.5 mL serum
Rejection Criteria
SST tube not acceptable.
Additional Information

Test sent to Mayo Medical Laboratories.

CPT Code
80299 x2