Role of Serologic Tests in Diagnosis of Viral Conjunctivitis (Pink Eye) Viral conjunctivitis usually does not require laboratory tests for diagnosis. Serologic tests are not a necessity. This test requires 2 samples for testing. Both samples must have duration of 2 weeks in between. Viral conjunctivitis, on average, takes 2 weeks to resolve on its own. By the time patient provides second sample for testing they would be on their way to recovery. Thus, serologic test does not seem to be the best fit for testing vial conjunctivitis as the results may not be accurate.