How the Test is Performed

Colonies of microorganisms are combined with different antibiotics to see how well each antibiotic stops each colony from growing. The test determines the effectiveness of each antibiotic against a particular organism.

How to Prepare for the Test

There is no special preparation.

How the Test Will Feel

The way the test feels depends upon the method used for obtaining the specific culture.

Why the Test is Performed

The test shows which antibiotic drugs should be used to treat an infection.

Because many organisms continue to show resistance against various antibiotics, sensitivity tests have become more and more important. Your doctor may start you on one antibiotic, but later change you to another one because of the results of sensitivity analysis.

What Abnormal Results Mean

If the organism shows drug resistance to the antibiotics used in the test, then those antibiotics will not be effective treatment.

Risks

The risks depend upon the method used for obtaining the specific culture.

Alternative Names

Antibiotic sensitivity

References

Smith MB, Woods GL. In vitro testing of antimicrobial agents. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2006:chap 57.

Update Date: 2/1/2012

Reviewed by: Linda Vorvick, MD, Family Physician, Seattle Site Coordinator, Lecturer, Pathophysiology, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.