Category Archives: LAB DIAGNOSIS

EYE SWAB AND SCRAPING FOR FUNGAL DETECTION


• Pus and discharge samples can be collected with a cotton wool swab and sent using standard precautions to the lab.

• Due to the sensitivity of the region and serious consequences of error, only an experienced ophthalmologist collects eye samples (e.g. corneal scrapings, intraocular fluid aspirate and swabs).

• For corneal scrapings, inoculate media plates and prepare slides at the patient’s side. Always contact the laboratory to obtain suitable media prior to the procedure. Alternatively, send corneal scrapings directly to the laboratory.

• Intraocular fluid (vitreous and aqueous) is collected using specialised equipment in the operating room.

• If sample is insufficient to perform both smear and inoculation of plates, give priority to culture.

• In case of contact lens-related infections, send contact lenses, case and cleaning solution to the lab for culture as well. Ear Swab and Scraping

• A physician collects samples from outer and middle ear. Skin scrapings from the external auditory canal are preferred. Use a sterile swab stick to collect exudates or debris.

• For deeper ear infections and to avoid damage to the ear drum, an ENT surgeon or experienced physician should use a speculum to draw specimen.

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SPUTUM, TRACHEAL ASPIRATE & LAVAGE FOR FUNGAL DETECTION

Sputum

• Patient submits the first morning expectorated sample (optimal) with the following instructions:

• Clean mouth with several rinses of sterile saline or water.

• Cough out 2-5 ml of sputum (not saliva) in a wide-mouthed sterile container.

• In case of dry cough, perform sputum induction with hypertonic saline nebulisation.

• Acceptability of sputum is determined with a Gram stained smear (pus cells >25/LPF, epithelial cells and only representative samples are accepted.

• 24-hour sputum collections are not acceptable.

Tracheal Aspirate

• Tracheal aspirates are collected through an endotracheal tube and are subject to the same limitations as sputum specimens.

Non-Directed Bronchoalveolar Lavage

• This method provides a lower respiratory tract sample without the need for bronchoscopy.

• A trained physician passes a suction catheter down the endotracheal tube until resistance is met.

• Inject an aliquot of sterile saline and then aspirate at least 1 ml of secretions.

• Non-directed techniques have been found to give results comparable to bronchoscopic methods.

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