This test is used to monitor levels of the antimicrobial drug 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.
here is no widespread consensus on the use of the vancomycin test and when to order it. Some health 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.
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 health 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.
- Sample of blood serum
- We perform the test daily