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Fungi

Suitable containers

Skin and nail samples should be collected into a Dermapak. If these are not available then a sterile universal may be used. Please do not use non sterile packets or sellotape as the culture may fail due to contamination with environmental fungi.

Skin swabs will NOT be processed for full fungal investigations.

Please provide one request form per sample.  A Dermapak is not a suitable request form.

Clinical details

Please include the following information if relevant:

  • Description of the lesion(s)
  • Diabetes
  • Immuno-compromised
  • Travel history – SE Asia, Americas
  • Contact with animals – specify

If Pityriasis versicolor is suspected please note clearly on the request form as this will significantly affect the report. This organism cannot be grown using conventional culture techniques and so the microscopy is heavily relied upon.

Storage of specimens

Skin and nail specimens should be stored at room temperature, as dermatophyte growth may be compromised between 4 - 6 oC.

Request forms

Only skin, hair and nail samples will be investigated for fungi (dermatophytes and saprophytes) this can take up to 3 weeks. If Candida is suspected ensure this is written in the clinical details. The following will always be investigated for Candida:

  • Diabetes
  • Immuno-compromised
  • Line sites
  • Ears
  • Paronychia
  • Skin folds
  • Mouths

Reports

A microscopy result will be issued within 24hrs of receipt of sample (Mon-Fri). The culture can take up to 3 weeks to grow. Calcofluor white is used for the microscopy, it is a fluorescent stain that highlights any fungal elements present in the sample.

The microscopy result will identify presence of fungal elements whether viable or not. The culture result being negative even with a positive microscopy as different pieces of skin and nail are used for each test.

Potentially significant saprophytic moulds will be reported with an explanation as not they will not always be the cause of the infection, this will be dependent on the clinical history and presentation of the patient.

Skin scrapings

In patients with suspected tinea or ringworm the area should be cleaned with an alcohol wipe (70% alcohol) before taking the sample. This will remove any potential contamination and ointments.

Using a sterile blunt implement, scrape the lesion, particularly at the advancing edge. If there are multiple lesions choose the most recent for testing as the older the lesion the less likely that viable organism will be present. Please send plenty of scrapings as at least 9 pieces are required for a full microscopy and culture.

It is vital that good quality samples are sent to the laboratory for testing as the results could be misleading and result in a false negative report.

Nail clippings

If possible, collect the sub-ungual debris in addition to nail clippings. Take pieces of the discoloured, dystrophic or brittle parts of the nail only, sampling as far back as possible from the distal part of the nail. At least 9 pieces are required for a full test. If there is insufficient then only a microscopy will be carried out.

Hair samples

Only send plucked hairs from the affected area along with some scalp scrapings. Cut hair is not suitable as the infection tends to affect just near or below the surface of the scalp. Please send at least 8 pulled hairs for testing.

 

(Modified Last By: AOM)