Antimicrobial Level - Cycloserine, Serum or Plasma
Also known as: CYCLOS
Use
The Antimicrobial Level - Cycloserine test measures the concentration of cycloserine in serum or plasma to ensure appropriate therapeutic levels are achieved for the treatment of mycobacterial infections. Accurate measurement informs treatment decisions as therapeutic ranges have been established, with a target concentration of 20 to 35 mcg/mL two hours post-dose. Elevated levels above the therapeutic range may result in central nervous system (CNS) side effects, while under-target levels may indicate suboptimal dosing or incorrect sample timing.
Special Instructions
This test is performed by National Jewish Health and is not carried out at ARUP Laboratories. Clinicians must prepare separate specimens if multiple tests are requested. Additionally, this test is not approved for testing in New York State and requires specific approval from the New York Department of Health before sample submission. Prompt handling is crucial; separate and freeze the specimen immediately after collection to preserve its integrity.
Limitations
The test results must be interpreted in the context of the dosing and timing relative to the patient's last dose; discrepancies in timing may impact the accuracy of the concentration measurement. The assay cannot distinguish between cycloserine and other structurally similar compounds, such as cyclosporine. It is recommended to consider patient-specific factors such as renal function, which may affect cycloserine levels, as well as other medications that may interact or cause cross-reactivity in the assay.
Methodology
Other
Biomarkers
Result Turnaround Time
13-17 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
0.5 mL
Container
ARUP standard transport tube
Collection Instructions
Collect in plain red tube or green (sodium or lithium heparin) tube. Separate serum from cells ASAP or within one hour of collection. Transfer to transport tube and freeze immediately.
Storage Instructions
Critical frozen. Stability: Ambient and refrigerated conditions are unacceptable, frozen stability is 1 month.
Causes for Rejection
Severely hemolyzed or thawed specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | Unacceptable |
| Frozen | 1 month |