MicrobiologyDermatology

Slit Skin Smear (2 Site)

Normal Range
0 (Negative)
Sample Type
Skin Scrape
Fasting
No
Unit
Bacteriological Index (BI)

Function

The Slit Skin Smear (SSS) is a microscopic examination used to detect Acid-Fast Bacilli (AFB), specifically Mycobacterium leprae, the causative agent of Leprosy (Hansen's Disease). By taking samples from specific sites (often earlobes and active skin lesions), clinicians can visualize the density and morphology of the bacteria.

Why it is Ordered

This test is ordered when a patient presents with suspicious skin lesions characterized by loss of sensation, or thickened nerves. It is used to confirm a diagnosis of leprosy, classify the disease into Paucibacillary (PB) or Multibacillary (MB) types, and monitor the response to Multi-Drug Therapy (MDT). The Bacteriological Index (BI) provides a logarithmic scale of the bacterial density.

Associated Conditions

  • Lepromatous Leprosy: Usually shows high BI (many bacilli).
  • Tuberculoid Leprosy: Often shows zero or very low BI despite clinical symptoms.
  • Relapse: An increase in BI after successful treatment may indicate a relapse.

Check Your Result

Check Your Result

Interactive
Bacteriological Index (BI)

Enter your lab result to see where you stand compared to the standard reference range.

Why Context Matters

The Slit Skin Smear has high specificity but low sensitivity, especially in the Tuberculoid form of the disease where bacteria are scarce. A negative result never rules out leprosy. The quality of the smear depends heavily on the technique (the 'slit' must be deep enough to reach the dermis but shallow enough to avoid excessive bleeding, which dilutes the sample). A second opinion or a skin biopsy for histopathology is often required if clinical suspicion is high.

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

Clinical References

Source-of-truth databases and clinical guidelines for Slit Skin Smear (2 Site):

Related Indicators

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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