To measure and monitor the level of vancomycin in your blood
Vancomycin
Vancomycin
This article was last reviewed
on
This article waslast modified
on October 29, 2018.
At a Glance
Why Get Tested?
When To Get Tested?
At intervals during vancomycin treatment
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None, but timing of the sample for testing is important; samples are typically collected just before the next dose (trough level). Follow any instructions provided.
Accordion Title
Common Questions
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How is it used?
This test is used to monitor levels of the antibiotic vancomycin in the blood. When a person takes a dose of vancomycin, the amount in the blood rises for a period of time, peaks, and then begins to fall, usually reaching its lowest level, or trough, just before the next dose. The next dose is timed to coincide with the falling concentration of the drug in the blood.
Because the goal is to administer the vancomycin such that a minimally effective concentration is always maintained in the blood, measurement of blood levels is usually timed to reflect the trough and, sometimes peak, to evaluate the adequacy of dosing and clearance of the drug from the body. Trough levels are collected just prior to a person's next vancomycin dose. Peak levels are collected 1 to 2 hours after the completion of the intravenous vancomycin dose.
The trough and sometimes peak values are used by clinical pharmacists and healthcare practitioners to calculate rates of absorption and clearance of the drug. These results are then used to determine the appropriate amount of drug and the appropriate timing between doses to assure that the blood concentration remains in the therapeutic range.
For additional information on how the test is used, see Therapeutic Drug Monitoring.
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When is it ordered?
There is no widespread consensus on the use of the vancomycin test and when to order it. Some healthcare practitioners will order trough levels every few days throughout vancomycin treatment. Some will order both trough and peak concentrations at regular intervals. Many do not feel that general monitoring is necessary and will only order the tests for those who are at increased risk of kidney damage (nephrotoxicity), who are taking concurrent medications, who have decreased kidney function, or who are not responding to treatment as expected.
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What does the test result mean?
Guidelines from 2009 by pharmacists and infectious disease specialists recommend that only trough levels be performed, with a minimum of 10 mcg/mL considered necessary to control an infection. The guidelines recommend a therapeutic range of 15-20 mcg/mL for significant infections. However, many institutions have specific ranges depending on the site of infection and severity of infection.
If trough levels of vancomycin are above the minimum level, then the person should be receiving enough of the drug to be effective. If the person's infection is not responding to the treatment, then the healthcare practitioner may either continue the drug for a longer period of time or consider other treatment options. If peak concentrations are below maximum levels, then the treated person is at less risk of developing nephrotoxicity and/or ototoxicity but may still experience either complication. Peak concentrations may vary, depending on the consistency of collection timing and on changing drug clearance rates.
If the trough and/or peak concentrations are above the maximum levels, then the person is at an increased risk of toxicity and the healthcare practitioner may either alter the dose or the dosing schedule.
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Is there anything else I should know?
An intravenous vancomycin dose must be given slowly. People given the dose at a rapid rate are at an increased risk of developing "red man syndrome," a histamine reaction that causes flushing of the face, a rash on the upper body, and a significant drop in blood pressure.
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Why isn't vancomycin more widely used?
The medical community tries to be conservative in its use of vancomycin, reserving it for patients with few other treatment options to stave off the emergence of vancomycin-resistant microbes. In recent years, some resistant and intermediate (decreased sensitivity) strains of Staphylococcus aureus (called VISA and VRSA for Vancomycin Intermediate/Resistant Staphylococcus aureus) and strains of Enterococcus (Vancomycin-Resistant Enterococcus or VRE) have emerged.
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Will I be tested if I am taking oral vancomycin?
Oral vancomycin therapy is rarely monitored as only tiny amounts of the drug are absorbed and carried in the blood. Occasionally, someone with impaired renal function will be monitored to verify that the drug is not building up in their body.
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Can I test vancomycin levels at home?
Although someone may receive intravenous vancomycin therapy at home, usually administered by a home health professional, blood levels cannot be monitored at home. The test requires specialized equipment and must be performed in the laboratory. The home health professional may draw a blood sample prior to administering the next dose of drug. This sample will be sent to a laboratory for analysis.
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Do some medicines interact badly with vancomycin?
Some drugs do interact with vancomycin. Tell your healthcare practitioner if you are taking any other medicines, especially aminoglycosides, amphotericin B, bacitracin, cisplatin, colistin, polymyxin B, or viomycin. These drugs may increase risk of side effects including kidney toxicity or hearing loss.