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HelpTest Code PLFA Cryptococcus Antigen Screen, Lateral Flow Assay, Pleural Fluid
Additional Testing Requirements
Pleural fluid testing for cryptococcal antigen should also be submitted for routine fungal culture. Order FGEN / Fungal Culture, Routine.
Specimen Required
Container/Tube: Sterile vial
Specimen Volume: 0.5 mL
Useful For
Diagnosis of infection with Cryptococcus species
Disease States
- Cryptococcosis
Testing Algorithm
If this screen is positive, the antigen titer will be performed at an additional charge.
Reporting Name
Cryptococcus Ag Screen, LFA, PFSpecimen Type
Pleural FluidSpecimen Minimum Volume
0.25
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Pleural Fluid | Refrigerated (preferred) | 21 days | |
| Frozen | 30 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Reference Values
Negative
Supportive Data
Sixty pleural fluid samples, including 30 specimens collected from patients without microbiologic testing ordered and 30 specimens spiked at various dilutions with Cryptococcus antigen (CrAg)-positive specimens, were evaluated by both the IMMY CrAg lateral flow assay (LFA) and the Meridian Cryptococcus antigen latex agglutination (CALAS) assays. The results are summarized in Table 1.
Table 1. Comparison of the IMMY CrAg LFA and the Meridian CALAS assays
|
Meridian CALAS result |
Positive agreement (95% CI) |
Negative agreement (95% CI) |
Overall agreement (95% CI) |
|||
|
Positive |
Negative |
81% (65.4-90.8) |
100% (86.5-100) |
89.5% (79.6-95.1) |
||
|
IMMY LFA result |
Positive |
23 |
7(a) |
|||
|
Negative |
0 |
30 |
||||
(a)Details for these 7 discordant samples are provided in Table 2. All 7 specimens were pleural fluid spiked with CrAg-positive material and were expected to be positive by both assays.
Table 2. Comparison of discordant specimens between the IMMY CrAg LFA and Meridian CALAS Assays
|
Sample |
Meridian qualitative result |
LFA qualitative result |
LFA quantitative result |
|
1 |
Negative |
Positive |
1:10 |
|
2 |
Negative |
Positive |
1:2 |
|
3 |
Negative |
Positive |
1:10 |
|
4 |
Negative |
Positive |
1:2 |
|
5 |
Negative |
Positive |
1:5 |
|
6 |
Negative |
Positive |
1:160 |
|
7 |
Negative |
Positive |
1:80 |
The IMMY CrAg LFA has been shown to be significantly more sensitive in both serum and CSF specimens in prior studies.(1) Our findings in pleural fluid are consistent with these previous studies.
The reportable range for this assay is 1:2 to 1:2560 and the reference range is negative. Cross-reactivity was not observed with specimens positive for Histoplasma capsulatum or Aspergillus species antigens.
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 to 2 daysSpecimen Retention Time
7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
87899-Cryptococcus Ag Screen, LFA, PF
87899-Cryptococcus Ag Titer, LFA, PF (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PLFA | Cryptococcus Ag Screen, LFA, PF | 29533-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 42396 | Cryptococcus Ag Screen, LFA, PF | 29533-7 |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| PLFAT | Cryptococcus Ag Titer, LFA, PF | No | No |
Forms
If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.