MicrobiologyInfectious Disease

Swab for Culture and Sensitivity

Normal Range
No pathogenic growth
Sample Type
Swab
Fasting
No
Unit
N/A

Function

The Swab Culture and Sensitivity test is designed to isolate and identify infectious microorganisms (bacteria or fungi) from various body sites, such as wounds, the throat, nasal passages, or surgical sites. Once an organism is grown, the laboratory tests various antimicrobial agents against it to determine which medications effectively inhibit its growth.

Why it is Ordered

This test is indispensable when an infection is suspected but the causative agent is unknown. It is ordered for:

  • Non-healing or purulent (pus-filled) wounds.
  • Sore throats suspected of being 'Strep throat'.
  • Suspected MRSA colonization in the nares.
  • Post-operative site redness or drainage.

Associated Conditions

  • Pyogenic Infections: Caused by Staphylococcus aureus or Streptococcus pyogenes.
  • Pharyngitis: Identifying Group A Strep to prevent complications like rheumatic fever.
  • Fungal Skin Infections: Identifying Candida species in skin folds.
  • Drug-Resistant Infections: Detecting MRSA or VRE to implement contact precautions and specific therapy.

Accurate culture results ensure that patients receive the correct antibiotic, preventing the development of antibiotic resistance and reducing the duration of illness.

Why Context Matters

Second opinions are useful if a culture returns 'mixed flora' or 'commensal organisms,' which may mask an underlying pathogen. Factors that invalidate results include taking antibiotics before the swab was collected, which suppresses growth. Additionally, if the swab was not transported in the correct medium or at the right temperature, fragile anaerobic bacteria may die before reaching the lab, leading to a false negative.

Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.

Related Indicators

Albert's Stain

View Range

Spore Stain

View Range

AFB Culture (Radiometric)

View Range
DR

Medically Reviewed by Dr. Binoy Babu, MBBS

Board Certified Doctor • 10+ Years Clinical Experience

Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.

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