Fungitell (Sendout)

Reference Values:

Interpretation:

The Fungitell assay should be used in conjunction with other diagnostic procedures, such as routine bacterial/fungal cultures, histologic examination of biopsy material, and radiologic studies.

Positive: (1,3)-Beta-D-glucan detected. A single positive result should be interpreted with caution and correlated alongside consideration of patient risk for invasive fungal disease, results of routine laboratory tests (eg, bacterial and fungal culture, histopathologic evaluation), and radiologic findings. Repeat testing on a new sample (collected in 3-4 days) is recommended as serially positive samples are associated with a higher diagnostic odds ratio for invasive fungal infection compared to a single positive result.

False-positive results may occur in patients who have recently (in the past 3-4 days) undergone hemodialysis, treatment with certain fractionated blood products (eg, serum albumin, immunoglobulins), or those who have had significant exposure to glucan-containing gauze during surgery.

Indeterminate: Repeat testing on a new sample is recommended in patients at risk for an invasive fungal infection.

Negative: No (1,3)-Beta-D-glucan detected.

This assay does not detect certain fungi, including Cryptococcus species, which produce very low levels of (1,3)-beta-D-glucan (BDG) and the Mucorales (eg, Lichtheimia, Mucor, and Rhizopus), which are not known to produce BDG. Additionally, the yeast phase of Blastomyces dermatitidis produces little BDG and may not be detected by this assay.

Cautions:

(1, 3)-Beta-D-glucan (BDG) is not present in the Mucorales (eg, Lichtheimia, Mucor, Rhizopus), Cryptococcus species, or Blastomyces species. Therefore, invasive fungal infection with any of these agents will lead to a negative BDG result.

BDG results should be interpreted alongside other diagnostic testing results, including culture, molecular assays, or serology.

False-positive BDG results have been documented in patients having undergone recent hemodialysis, those that have received certain fractionated blood products (eg, albumin, immunoglobulins), and those who have had exposure to high amounts of glucan-containing gauze during surgery. BDG levels normalize approximately 3 to 4 days following these events.

Single time-point testing with the BDG assay is associated with limited clinical sensitivity and specificity. Serial testing, at least 2 times per week, is associated with higher diagnostic odds ratio (DOR 112) for the presence of an invasive fungal infection in an at-risk patient compared to single time-point positive result (DOR 16).

The BDG assay does not identify or indicate the presence of a specific fungal organism.

Serial testing to document BDG levels may be used to monitor disease progression and response to therapy; however, data on the clinical utility and accuracy of this practice is limited.

3 mL blood in GOLD TOP SST

Unacceptable: Red top tube or any other tube type.

Note: This test requires a dedicated tube. The sample cannot be shared or used for other testing. Avoid exposure of specimen to atmosphere to prevent environmental contamination of the sample.

Outside Laboratories: This test requires a dedicated collection tube.

• Centrifuge sample. Do not aliquot or open the tube.
• Refrigerate spun sample.

Stability: Refrigerated (preferred): 14 days; Frozen: 30 days; Ambient: Unacceptable.

Centrifuge within 2 hours of collection and refrigerate unopened sample. Do not aliquot or open the tube.

FHCC, UW-NW, HMC: Centrifuge within 2 hours of collection and refrigerate unopened sample before forwarding to UW-MT for sendout. Do not aliquot or open the tube.

Sendouts:

• Order Mayo Test: SFUNG.
• Interfaced: Yes.

Stability: Refrigerated (preferred): 14 days; Frozen: 30 days; Ambient: Unacceptable.

Reject Due To: Gross hemolysis, lipemia, or icterus; sample that has been opened/exposed to potential environmental contamination.