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|Test Update Information||Vancomycin assay changed from the Siemens Centaur method to the Beckman DxC method on 3/26/2012. The DxC assay yields vancomycin levels that average approximately 20% lower than the Centaur assay and are in better agreement with results reported with most other vancomycin assays in proficiency testing surveys.|
|Utilization Guidelines||VANCOMYCIN TROUGH MONITORING
Vancomycin troughs are not recommended in patients in whom anticipated duration of therapy is short (≤ 3 days)
Only trough levels should be obtained. Vancomycin peaks have no clinical significance. Trough levels should be obtained within 30 minutes before 4th dose of a new regimen or dosage change.
INDICATIONS FOR VANCOMYCIN TROUGHS
Patients with unstable renal function or when serum Cr may not accurately reflect GFR i.e. patients > 70, reduced muscle mass (e.g. malnutrition, prolonged hospitalization, amputees, etc.)
Patients on continuous or intermittent hemodialysis (for intermittent HD draw a pre-dialysis level)
Patients with severely altered volumes of distribution (e.g. morbid obesity, significant edema, burns)
Initial and definitive therapy of suspected central nervous system infections, endocarditis, ventilator-associated pneumonia, bacteremia or osteomyelitis caused by MRSA.
FREQUENCY OF VANCOMYCIN TROUGHS
Once weekly monitoring is reasonable in patients with stable renal function. (Data supporting safety of prolonged troughs of 15-20 mcg/ml is limited.)
|Performed by||Parnassus Chemistry|
|In House Availability||Test available 24 hours per day 7 days a week|
|Method||Turbidimetric inhibition immunoassay (Beckman DxC800)|
|Collection Instructions||Time to steady state: 3 doses
Collect trough samples ≤ 30 minutes prior to 4th or subsequent dose. For patients on hemodialysis collect prior to dialysis.
Note exact time of collection on requisition AND sample.
|Container type||Gold top or Light Green top, CSF tube or sterile collection tube|
|Amount to Collect||1 mL blood|
|Sample type||Serum or plasma, CSF|
|Preferred volume||0.5 mL serum or plasma|
|Min. Volume||0.2 mL serum or plasma|
|Processing notes||Refrigerate serum.|
Source of reference range: UCSF/SFGH/VASF joint guidelines for antimicrobial use in adults.
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|Turn around times||1 day|
|Additional information||Only a trough sample is recommended. If a peak level is deemed necessary, obtain the sample 60 min. after the end of the infusion.
Peak levels in the range of 30 – 40 mg/L may be expected with usual dosing. Toxicity may occur with vancomycin levels > 80 mg/L.
Therapeutic trough 10-20 mg/L recommended typically. However, for patients with serious MRSA infections (central nervous system infections, endocarditis, ventilator-associated pneumonia, bacteremia or osteomyelitis) trough levels of 15-20 mg/mL and ID consult are recommended.
Note: some monoclonal proteins may cause falsely low vancomycin results. The presence of human anti-mouse antibodies or heterophile antibodies may also interfere with the vancomycin assay in some cases. Testing for vancomycin levels in parallel dilution studies and with a different assay may be useful in cases where interference by a monoclonal protein or abnormal immunoglobulin is suspected.
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|Last Updated||11/21/2013 12:58:30 PM|
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