Sign in →

Test ID: RIBAV Ribavirin, Serum

Reporting Name

Ribavirin, S

Useful For

Assessing adequacy of ribavirin therapy or potential drug-related toxicity

Specimen Type


Specimen Required

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Draw blood immediately before next scheduled dose.

2. Centrifuge and separate serum from cells or gel within 2 hours of draw.

3. Delay in removing serum may result in falsely-decreased ribavirin concentrations.

Specimen Minimum Volume

0.2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  28 days
  Ambient  72 hours

Reference Values

2,500-4,000 ng/mL

Day(s) and Time(s) Performed

Monday; 4 p.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
RIBAV Ribavirin, S 41469-8


Result ID Test Result Name Result LOINC Value
60536 Ribavirin, S 41469-8

Clinical Information

Ribavirin is a nucleoside analog with antiviral activity against a number of RNA and DNA viruses, including hepatitis C virus (HCV). In combination with interferon, ribavirin is a treatment of choice for chronic HCV infection. In this setting, higher serum concentrations of ribavirin appear to correlate with the likelihood of achieving virological response; however, the drug dose is limited by concentration-dependent hemolytic anemia. Although no consensus therapeutic targets or toxic thresholds have been established, ribavirin concentrations between 2,500 and 4,000 ng/mL have been suggested to improve virological response and minimize toxicity.


The half-life of ribavirin is very long, typically 5 days or more. For this reason, steady-state concentrations are not achieved until several weeks into therapy; most studies have performed initial therapeutic monitoring after at least 28 days of ribavirin treatment. Specimens should be drawn immediately prior to the next scheduled dose, or at minimum of greater than12 hours after the last dose.


Elimination of ribavirin is also very slow, and due to incorporation of the drug into red blood cells, may take up to 6 months after the cessation of therapy. Ribavirin has shown teratogenic activity in animal models, thus patients are recommended to practice stringent birth control until at least 6 months after the end of treatment.

Clinical Reference

1. Jen JF, Glue P, Gupta S, et al: Population pharmacokinetic and pharmacodynamic analysis of ribavirin in patients with chronic hepatitis C. Ther Drug Monit 2000;22(5):555-65

2. Marquet P, Sauvage FL, Loustaud-Ratti V, et al: Stability of ribavirin concentrations depending on the type of blood collection tube and preanalytical conditions. Ther Drug Monit 2010;32:237-241

3. Pedersen C, Alsio A, Lagging M, et al: Ribavirin plasma concentration is a predictor of sustained virological response in patients treated for chronic hepatitis C virus genotype 2/3 infection. J Viral Hepatitis 2011;18(4):245-51

Analytic Time

2 days

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)


If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.

Mayo Clinic Laboratories | Therapeutics Catalog Additional Information:
mml-antivirals, mml-drugmonitoring