1. How should specimens be stored? How long may they be stored prior to testing?
- Formalin, SAF: Room temperature (20 - 30ºC), refrigeration (2 - 8ºC), or frozen (-20 or -70ºC). Sample must be tested within 2 months after collection.
- MIF: Room temperature (20 - 30ºC), refrigeration (2 - 8ºC), or frozen (-20ºC). Sample must be tested within 2 months after collection.
- Cary Blair: Refrigeration (2 - 8ºC). Sample must be tested within 2 weeks after collection. Frozen (-20ºC). Sample must be tested within 2 months after collection.
- Stuart's Medium, Fresh Stool: Testing should be performed as soon as possible. Storage validation has not been performed.
2. Can a stool specimen collected in ECOFIX™ be tested with this kit?
No. Specimens collected in ECOFIX have not been validated for use with this kit. It is believed that there is a fixative in this product that binds the membrane.
3. Can this kit be stored at room temperature?
No. This kit is extremely temperature sensitive and must be kept in refrigeration (2 - 8º) at all times when not in use. All kit reagents, and any samples being tested, must be at room temperature (20 - 30ºC) prior to testing.
4. May results be read outside of the 10-15 minute time suggested?
No. This kit uses lateral flow technology, which makes it very sensitive to the read time. Reading too soon may cause a false negative result. Reading the device after the appropriate read-time may cause "reverse-flow" to occur, which can create a false positive line at either the "Giard" or Crypt" position.
5. What factors could be the cause of a false positive result?
- Inappropriate sample medium being used.
- Storage of sample at wrong temperature or length of time.
- Read time. Extended read times can cause "reverse-flow", which can create a false positive line at either the "Giard" or "Crypt" position.
- Temperature of kit and sample being tested. All kit reagents, and any samples being tested, must be at room temperature (20 - 30ºC) prior to testing.
6. What could be the cause of a false negative test result?
- Inappropriate sample medium being used
- Storage of sample at wrong temperature or length of time.
- Read time. Results read too early may cause a false negative test result.
- Temperature of kit and sample being tested. All kit reagents, and any samples being tested, must be at room temperature (20 - 30ºC) prior to testing.
- Handling of test device. Test device must be opened JUST PRIOR to testing. Results may be affected by a device being left out of packaging for an extended time before use.
- mproper mixing of specimen. False negative results can occur when improper mixing has been performed, especially with solid or hard to mix specimens.
- Antigen level. Sample may contain a level of antigen that falls below the detection limit of this assay.
- Amount of specimen being tested. Testing has only been validated for use with a sample size of approximately 60 µL. Be sure that the pipet is filled completely and that the total amount of specimen is being dispensed.
- Reading of line intensity: A visible line of any intensity, at either test position, is indicative of a positive result. The line does not have to be as dark as the control line.
7. What could cause a beaded, or incomplete, line at either test position?
This may be caused by the presence of excessive particulate matter in the specimen being tested. Any beaded or incomplete line at either test position constitutes an indeterminate result. Testing should be repeated on a separate testing device. If repeat testing does not resolve the issue the sample should be diluted two-fold in same transport medium in which it was originally collected, and then run on a new testing device.
8. Can extra Sample Treatment Buffer or Conjugate Reagents be purchased if the kit runs short?
No. All kits are matched. Contact BD Technical Service if a kit does not contain enough reagents to run 30 tests.
9. What are the specific Giardia and Cryptosporidium antigens detected by this assay?
The Giardia antigen detected in the assay is known in the literature as Cyst Wall Protein 1 (CWP1) or GSA-65. It is present on both trophozoites and cysts. The Cryptosporidium antigen has not been well characterized in the literature. It is believed to be a glycoprotein found on oocysts. Even though both antigens originate from cells, they appear to be present in a soluble form in clinical stool specimens, based on the observation that they don't concentrate with centrifugation.
