Sensitivity analysis

Definition

Sensitivity analysis determines the effectiveness of antibiotics against microorganisms such as bacteria that have been isolated from cultures.

Sensitivity analysis may be performed along with:

• Blood culture
• Clean catch urine culture or catheterized specimen urine culture
• Sputum culture
• Culture from endocervix
• Throat culture
• Wound and other cultures

Alternative Names

Antibiotic sensitivity

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.

What the risks are

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

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.