Mycobacterium – detection – Corneal scrapings

Alternative Names/Synonyms	Detection of acid fast bacilli in corneal scraping specimens
Laboratory	Microbiology
Sub-section	Bacteriology
Specimen Type	○ Corneal scrapings

Specimen Requirements (Tube Type)

○ Corneal scrapes: MGIT tube, 2 LJ agar slants, microscope slide (contact the microbiology laboratory to obtain collection supplies

Collection Requirements

Corneal Scrapes:
○ For corneal scrapes, corneal surfaces should be rinsed thoroughly with sterile normal saline to remove anaesthetic prior to collecting specimen; use a Kimura scalpel to scrape across the ulcer using short firm strokes in one direction; obtain 3 to 5 scrapings per cornea. Avoid contact with eyelids/eyelashes. Inoculate scrapings into MGIT tube, LJ agar slants, and onto microscope slide and place slide into slide holder.

Sample Stability

Refer to section Sample Processing / Delivery

Referral Laboratory

Public Health Ontario Laboratory (PHOL)

Routine Turnaround Time

○ Microscopy: 1 day
○ Culture: Up to 49 days; a positive culture is reported within 24h of growth

Laboratory Contact Information

416-586-4800 extension 4432

Special Instructions

Approval Required

Sample Processing / Delivery

○ Label specimen container. Place specimens in biohazard bag and seal.
○ Specimens should be stored at refrigeration temperature (2-8˚C) after collection if transport is delayed more than one hour.
○Transport to the UHN/SHS Microbiology Laboratory ASAP after collection
○The specimen will be referred to the Public Health Ontario Laboratory (PHOL) for testing