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Test Code VANRA Vancomycin, Random, Serum

Useful For

Monitoring adequacy of drug concentration during vancomycin therapy

 

Whenever a specimen is submitted or collected without collection timing information

Method Name

Immunoassay

Reporting Name

Vancomycin, Random, S

Specimen Type

Serum Red


Advisory Information


In addition to this random assay, both peak level and trough level testing are available.

1. Serum for a peak level should be drawn 1 hour after completion of dose (order VANPA / Vancomycin, Peak, Serum).

2. Serum for a trough level should be drawn no more than 30 minutes prior to next dose (order VANTA / Vancomycin, Trough, Serum).



Specimen Required


Collection Container/Tube: Red top
Submission Container/Tube:
Plastic vial

Specimen Volume: 0.5 mL
Collection Instructions: Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Refrigerated (preferred) 14 days
  Frozen  365 days
  Ambient  48 hours

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

NA

Icterus

NA

Other

Serum gel tube

Clinical Information

Vancomycin is an antibiotic used to treat infections caused by gram-positive organisms that are resistant to beta-lactam antibiotics, such as methicillin-resistant staphylococci (MRSA), Streptococcus viridans group, penicillin/cephalosporin-resistant Streptococcus pneumoniae, and penicillin/ampicillin-resistant Enterococcus species. The oral formulation, which is not absorbed, is used in the treatment of pseudomembranous colitis caused by Clostridium difficile. Vancomycin is also used when patients are intolerant or allergic to beta lactams.

 

Vancomycin has been associated with nephrotoxicity and ototoxicity, although it appears that many of these reports reflected impurities in early formulations. Monitoring of vancomycin-related nephrotoxicity is recommended only for patients with reduced renal function, those receiving aggressive or prolonged vancomycin regimens, or those at high risk including patients comedicated with other nephrotoxic agents.

 

Trough concentrations are recommended for therapeutic monitoring of vancomycin, preferably acquired at steady state (just before fourth dose). To avoid development of resistance, vancomycin trough levels should remain above 10.0 mcg/mL. Complicated infections require higher target levels, typically 15.0 to 20.0 mcg/mL. Peak concentrations do not correlate well to efficacy or nephrotoxicity, but may be useful for pharmacokinetic studies or for select patients.

 

Random levels may be ordered when attempting to determine when to dose vancomycin in patients with renal impairment or those undergoing dialysis.

Reference Values

Vancomycin, Trough

Therapeutic: 10.0-20.0 mcg/mL

Vancomycin, Peak

Therapeutic: 20.0-45.0 mcg/mL

These levels are consistent with Mayo Clinic Antimicrobial Therapy Guidelines.

Interpretation

Trough levels correlate better with efficacy than peak levels, with target trough levels of 10.0 and 20.0 mcg/mL, depending on the type of infection.

 

Peak levels are not recommended for monitoring, except in select circumstances such as when performing pharmacokinetic analyses (eg, area under the curve: AUC determinations). Typical peak levels are between 20.0 and 45.0 mcg/mL.

Cautions

As with any assay employing mouse antibodies, the possibility exists for interference by human antimouse antibodies (HAMA) in the sample, which could cause falsely lowered results.

 

Unspecific binding of heterophilic antibodies from the sample to glucose-6-phosphate dehydrogenase of the reagent may lead to falsely lower test results in very rare cases (<10[-6]).

Method Description

The assay is based on the kinetic interaction of microparticles in solution (KIMS). Vancomycin antibody is covalently coupled to microparticles and the derivative is linked to a macromolecule. The kinetic interaction of microparticles in solutions is induced by binding of drug-conjugate to the antibody on the microparticles and is inhibited by the presence of vancomycin in the sample. A competitive reaction takes place between the drug conjugate and vancomycin in the sample. A competitive reaction takes place between the drug conjugate and vancomycin in the serum sample for binding to the vancomycin antibody on the microparticles. The resulting kinetic interaction of microparticles is indirectly proportional to the amount of drug present in the sample.(Package insert: Roche Vancomycin reagent, Roche Diagnostic Corp, Indianapolis, IN.  2016-09 Ver. 1)

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Analytic Time

Same day/1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

80202

LOINC Code Information

Test ID Test Order Name Order LOINC Value
VANRA Vancomycin, Random, S 20578-1

 

Result ID Test Result Name Result LOINC Value
VANRA Vancomycin, Random, S 20578-1