Mycology (fungal) direct examination

TEST DESCRIPTION

Microscopic examination of clinical specimens for the presence of fungal elements. This method utilizes potassium hydroxide (KOH) and/or Calcofluor White staining techniques to identify elements such as yeast cells and hyphae. Rapid detection of fungal infections aids in appropriate early intervention.

Methodology

Tissue examination by KOH slide

Reference range

No fungal elements seen

TEST FREQUENCY & RESULT AVAILABILITY

Performed daily. Reports are issued within two business days of specimen receipt.

ACCEPTABLE SPECIMEN TYPES AND COLLECTION

• Any body fluid, scraping, or tissue except for blood is generally acceptable for mycological examination, including bone marrow specimens, sputum, bronchoalveolar lavage, transtracheal aspirate, bronchial brush, skin scrapings, hair, nails, abscess specimens, urine, CSF, and tissue and biopsy specimens
• Detailed collection instructions appear below for the most common specimens

SPECIMEN STORAGE

Most specimens should be stored at refrigerated temperature (2–8 °C/36–46 °F) for up to 24 to 72 hours. Bone marrow specimens must be received by the laboratory within 24 hours of collection. Some specimens (e.g., skin, hair, nails) may be stored at room temperature and do not have a specified holding time.

SPECIMEN TRANSPORT

Shipping conditions should follow the temperature and time requirements outlined above.

REJECTION CRITERIA

• Blood specimens
• Specimens placed in inappropriate preservatives such as formalin.
• Holding time exceeded: 
  1. Bone marrow specimens: >24 hours
  2. Other body fluids: >72 hours
  3. Skin scrapings, hair, nails, or culture: No specified holding time
• Dried out specimens other than hair, nails, and skin
• Specimens that were transported improperly.
• Improperly labeled specimens (i.e., labeling does not include patient identifiers)
• Dry swabs
• Leaking specimens
• Specimens comprised of insufficient material required for testing

CODES

CPT: 87220
LOINC: 667-6
Test code: 3900

TEST FEE

Refer to the current fee schedule.

DETAILED SPECIMEN COLLECTION INSTRUCTIONS

1. Any body fluid, scraping, or tissue except for blood may be subject to mycological examination. Acceptable limits for collection and transport for the most common are specimens are outlined below.
2. Bone marrow specimens
   1. Aseptically collect by sterile syringe or equivalent at least 0.3 ml to 1 ml in a sodium polyanethol sulfonate (SPS) or sodium heparin (heparin) blood tube. Store specimen at 2–8ºC. Transport refrigerated or ambient within 24 hours, avoid freezing.
3. Sputum
   1. Collect an early morning sputum produced by a deep cough into a sterile container. At least 5 ml of purulent material is optimal. Before collection, the mouth should be cleansed; remove dentures or brush teeth. Induced sputum is acceptable.
   2. Deliver specimen to the laboratory as soon as possible, preferably within 2 hours of collection. If the specimen must be held, store at 2–8ºC for up to 72 hours. Transport refrigerated. Never freeze the specimen.
   3. A fresh specimen is important because endogenous saprophytic organisms may overgrow the systemic pathogens or inhibit them by acidifying the culture media.
4. Bronchoalveolar lavage, transtracheal aspirate, bronchial brush
   1. Specimens are collected in a clinical setting; placed in a sterile container. 
   2. Bronchial brushes are placed in sterile saline, sterile distilled water, or brain heart infusion broth.
   3. Store specimen at 2–8ºC. Transport to the laboratory refrigerated within 72 hours. 
5. Skin scrapings
   1. Cleanse area with 70% alcohol and allow to air dry. Scrape the lesion margin and place the material in a dry sterile container, be sure to collect any moist exudate.
   2. Store and transport specimen at ambient or refrigerated temperature (2–8ºC), avoid freezing.
6. Hair
   1. Collect 10 to 20 hairs, best detected using a Wood’s Lamp (long wavelength UV lamp). Place in a sterile dry container. If no fluorescence is observed, scrape scalp scales and pluck hairs at the edge of infection.
   2. For Piedra, cut off several hairs with nodules attached.
   3. Store and transport specimen at ambient or refrigerated temperature (2–8ºC), avoid freezing.
7. Nails
   1. Cleanse nail area with 70% alcohol and allow to air dry. Clip or scrape affected areas of nail deeply enough to obtain recently invaded nail tissue. Also, scrape the nail bed to collect debris under nail. Place specimen in a dry sterile container. Store and transport at ambient or refrigerated temperature (2–8ºC).
8. Abscess specimens
   1. Abscess material is aseptically aspirated in a clinical setting using a syringe. Transport syringe without a needle or transfer material to a sterile screw-cap container. If the quantity is very small, 0.1 to 0.5ml of sterile saline may be added.
   2. If specimen is collected surgically, also submit a portion of the abscess wall.
   3. A non-cotton tip aerobic swab can be used, several, if possible, is optimal. Swabs for collection of material from draining fistulas and sinus tracts are the least preferred collection device.
   4. Store the specimen at 2–8ºC, transport refrigerated or ambient within 72 hours, avoid freezing.
9. Urine Specimens
   1. Collect 10 to 50 ml of clean-catch urine (first of the morning is best), catheterized urine, or suprapubic aspirate in a sterile screw cap cup. Store the specimen at 2–8ºC. Transport to the laboratory refrigerated within 72 hours, avoid freezing.
   2. Urine preservative collection systems can be used for urinary tract infection culture but are not acceptable for systemic pathogen culture. Follow the manufacturer’s transport and storage instructions for individual preservative systems.
10. Body fluids other than CSF
    1. Bloody specimens should be collected in a heparinized syringe. 
    2. Non-bloody specimens are submitted in sterile containers.
    3. A minimum of 1 ml should be collected. In general, the more fluid obtained for culture, the better the chance of isolation of any fungal pathogen.
    4. Store at 2–8ºC, transport refrigerated or ambient within 72 hours, avoid freezing.
11. CSF
    1. CSF is obtained by lumbar puncture. A minimum of 2 ml should be collected and placed in a sterile container.
    2.  Store at 2–8ºC, transport refrigerated or ambient within 72 hours, avoid freezing.
12. Tissue and biopsy specimens
    1. Generally, tissue and biopsy specimens are collected in a clinical setting and placed in a sterile screw-cap container with a small amount of sterile saline to prevent drying.
    2. Store at 2–8ºC. Transport specimen refrigerated or ambient within 72 hours, avoid freezing.