Bactrim (Sulfamethoxazole and Trimethoprim); Septra (Sulfamethoxazole and Trimethoprim)
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Trimethoprim, Serum
Test ID: TRIME S
Test
Aliases/Synonyms
Method
HPLC
Method Description
Acetonitrile precipitation with analysis by HPLC. (Unpublished Mayo method)
Report Includes
Trimethoprim
Specimens
Serum
Clinical Utility
Monitoring trimethoprim therapy to ensure drug absorption, clearance, or compliance.
Trimethoprim is coadministered with sulfamethoxazole for prophylaxis or treatment of bacterial infections. These agents are used to treat a variety of infections including methicillin-resistant Staphylococcus aureus, and for prophylaxis in immunosuppressed patients such as HIV-positive individuals.
Trimethoprim has a wide therapeutic index and dose-dependent toxicity. Trimethoprim accumulates in patients with renal failure.
Therapeutic drug monitoring is not commonly performed unless there are concerns about adequate absorption, clearance, or compliance. Accordingly, routine drug monitoring is not indicated in all patients.
Test Location
Mayo Clinical Labs, Minnesota USA
Test Version
27-Feb-2020
Specimen
Specimens
Serum
Collection Containers
Red top (no additive)
Sample Volume
1.0 mL
Minimum Volume
0.2 mL
Collection & Handling
Collection Instructions
Serum for a peak level should be drawn at least 60 minutes after a dose.
Handling Information
Separate within 2 hours.
Stability
| Ambient | 28 days |
|---|---|
| Refrigerated | 28 days |
| Frozen | 28 days |
Test Version
27-Feb-2020
Performance / Interpretation
Method
HPLC
Method Description
Acetonitrile precipitation with analysis by HPLC. (Unpublished Mayo method)
Turnaround Time
10 days
Results
| Name | Units | Reference Range | Conversion Factor | |
|---|---|---|---|---|
| Trimethoprim | mcg/mL |
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Most patients will display peak steady state serum concentrations >2.0 mcg/mL when drawn at least 1 hour after an oral dose. Target concentrations may be higher, depending on the intent of therapy.
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Test Location
Mayo Clinical Labs, Minnesota USA
Test Version
27-Feb-2020
Interface / Setup
HL7 Interface Codes
| Order Code | Result Codes | Units |
|---|---|---|
| TRIME S | 63338Trimethoprim, S | mcg/mL |
Test Version
27-Feb-2020