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This article waslast modified on 15 August 2023.
At a Glance
Why Get Tested?

To measure and monitor the concentration of vancomycin in the blood

When To Get Tested?

At the start of vancomycin treatment and intervals during treatment

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

None, but timing of the sample for testing is important; follow any instructions provided

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

This test measures the concentration of vancomycin in the blood. Vancomycin is an antibiotic 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 antibiotics such as methicillin, but has risen again with the emergence of methicillin-resistant strains of staphylococcus, such as Staphylococcus aureus (Methicillin Resistant Staphylococcus Aureus, MRSA).

Intravenous vancomycin may be given to treat infections such as septicaemia (infection of the blood), endocarditis (infection of the membrane surrounding the heart), osteomyelitis (infection of the bone), some pneumonias, and meningitis (infection of the spinal cord).  It is often the drug of choice for methicillin-resistant staphylococcus epidermidis and staphylococcus aureus infections, especially when they are associated with implanted devices such as heart valves, artificial hips, and indwelling catheters.  Vancomycin may also be given to prevent an infection (prophylactically) to some people before specific surgical and dental procedures where there is a high risk of MRSA. Vancomycin is normally given intravenously to get the drug into the circulation because vancomycin is poorly absorbed through the intestine. However, oral vancomycin may be prescribed to treat some resistant Clostridium difficile infections which occur in the gastrointestinal tract,where absorption into the circulation is not needed. Vancomycin may also be added to dialysis fluid to treat peritonitis associated with peritoneal dialysis.

The effectiveness of vancomycin depends on maintaining blood levels at a minimum concentration for the duration of therapy. It is also necessary to avoid excessive concentrations of vancomycin because high levels can result in damage to some organs, specifically the ears (hearing damage, ototoxicity) and kidney damage (nephrotoxicity). The dose of vancomycin to be given in individual circumstances depends on a variety of factors, including how well the kidney is functioning, the presence of other drugs which might have caused kidney damage and the patient’s age and weight.

Vancomycin is eliminated from the body through the kidneys. A patient with reduced kidney function may not be able to remove the drug from their system effectively, which will cause an increased concentration in the blood. Lower doses are used in patients with reduced kidney function, On the other hand, if a patient is given too little drug and is unable to maintain a sufficient minimum level in the blood, then it is unlikely that the infection will be completely eradicated. The vancomycin blood test can be 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?

None, but timing of the sample for testing is important; follow any instructions provided

Accordion Title
Common Questions
  • How is it used?

    When a vancomycin dose is given, its concentration in the blood first rises, reaches a peak level and then falls gradually. The next dose is timed to overlap the falling level so that a minimum concentration is always maintained in the blood. Measurement of blood levels is usually requested at times that reflect the lowest concentration (trough) and the highest concentration (peak) to evaluate the effectiveness of therapy. Trough levels are collected just prior to a patient’s next vancomycin dose. Peak levels are collected 1 to 2 hours after the end of the intravenous vancomycin dose. These results are then used to determine the appropriate amount of drug and the appropriate timing between doses to ensure that the blood concentration remains in the therapeutic range.

    For additional information on how the test is used, see Therapeutic Drug Monitoring.

  • When is it requested?

    Vancomycin should be measured on the second day of treatment, immediately before the next dose, and subsequent doses should be adjusted according to the vancomycin concentration. Some doctors will request trough levels every few days throughout vancomycin treatment. Some will request both trough and peak concentrations at regular intervals. Others do not feel that general monitoring is necessary and will only request the tests on patients who are at increased risk of kidney damage because of other medicine that they are taking or poor kidney function. They may also use the test on those who are not responding to treatment as expected. In pregnant women, there is a risk of toxic effects affecting the foetus. The drug is only used in pregnancy if the potential benefits outweigh the risks, and vancomycin concentration measurements are essential in this situation to reduce the risk of foetal toxicity.

  • What does the test result mean?

    If trough levels of vancomycin are above the minimum level, then the patient should be receiving enough of the drug to be effective.  If the patient’s infection is not responding to the treatment, then the doctor 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 patient is at lower 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 peak concentration is excessive, the doctor may either alter the dose or alter the dosing schedule.

  • Is there anything else I should know?

    An intravenous vancomycin dose must be given slowly. Patients 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 and upper body and a significant drop in blood pressure. Discontinuing the infusion results in resolution of the clinical features.

    Kidney function tests such as urea, creatinine and creatinine clearance may be requested prior to the start of vancomycin therapy and at intervals, or as needed, to evaluate changes in kidney status.

  • Why isn't vancomycin more widely used?

    The more widely an antibiotic is used, the more bacteria develop resistance to it. The medical community tries to be conservative in its use of vancomycin, reserving it for patients with severe illness and few other treatment options in order to reduce the emergence of vancomycin-resistant bacteria. In recent years, some resistant and intermediate (decreased sensitivity) strains of Staphylococcus aureus and strains of Enterococcus have emerged and antibiotic resistance is becoming an increasing problem in controlling serious infections.

  • 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, a patient with impaired renal function will be monitored to verify that the drug is not building up in the body.

  • Can I test vancomycin levels 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.

  • Should all antibiotic therapy be monitored like vancomycin?

    No, not all antibiotics require monitoring.  Unlike vancomycin, most antibiotics have a larger therapeutic range in which they are effective but will not cause side effects.  Because of this, they can be prescribed based upon pre-established dosing schedules.