At a Glance
Why Get Tested?
To measure and monitor the concentration of vancomycin in the blood
When to Get Tested?
At intervals during vancomycin treatment
A blood sample drawn from a vein in your arm
The Test Sample
What is being tested?
This test measures the concentration of vancomycin in the blood. Vancomycin is an antimicrobial that is used to treat serious infections caused by gram-positive bacteria. Developed in the 1950s, vancomycin was originally prescribed primarily when organisms proved resistant to penicillin or when a person was allergic to penicillin. Its use declined with the introduction of other antimicrobials such as methicillin, but has risen again with the emergence of methicillin-resistant strains of Staphylococcus, such as Staphylococcus aureus.
Intravenous vancomycin may be given to treat infections such as septicaemia, endocarditis (infection of the membrane surrounding the heart), osteomyelitis (infection of the bone), skin and soft tissue infections, some pneumonias, and meningitis. It is often the drug of choice for methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus infections. Vancomycin may also be given prophylactically (to prevent an infection) to some people before specific surgeries and dental procedures. Intravenous vancomycin administration is necessary to get the drug into the circulation because vancomycin taken by mouth is poorly absorbed. Oral vancomycin can be prescribed to treat some Clostridium difficile infections (either severe or relapsed infection). This is an infection that occurs in the gastrointestinal tract where absorption into the circulation is not needed.
The effectiveness of vancomycin depends on sustaining blood levels at a minimum concentration for the duration of therapy. Excessive concentrations of vancomycin must be avoided because high levels can result in toxicities - specifically ototoxicity (damage to hearing) and nephrotoxicity (kidney damage). The amount of vancomycin given per dose depends on a variety of factors, including kidney function, other nephrotoxic drugs the patient may be taking, age and weight.
A patient with decreased kidney function may not be able to clear the drug out of his/her system efficiently, resulting in increased concentration in the blood. If a patient is given too little drug and is unable to maintain a sufficient minimum dose in the blood, then it is unlikely that treatment will be effective. The vancomycin test is used to monitor the amount of drug in the blood to ensure that it is adequate but not excessive.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
Ask a Laboratory Scientist
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.