A rapid, one step test for the qualitative detection of Cryptosporidium and Giardia antigens in human faeces.
For professional in vitro diagnostic use only.
The Crypto-Giardia Device test is a rapid chromatographic immunoassay for the qualitative detection of Cryptosporidium and Giardia antigens in human faeces specimens to aid in the diagnosis of cryptosporidiosis and giardiasis.
Cryptosporidiosis is a diarrhoeal disease caused by microscopic parasites of the genus Cryptosporidium. Once an animal or person is infected, the parasite lives in the intestine and passes in the stool. The parasite is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very resistant to chlorine-based disinfectants. Both the disease and the parasite are commonly known as "Crypto."
Giardiasis is a diarrhoeal illness seen throughout the world. It is caused by a flagellate protozoan parasite, Giardia intestinalis, also known as G. lamblia and G. duodenalis.
Giardia is a common cause of gastrointestinal disturbance in both high- and low-income countries. The incidence of Giardia is generally higher in low-income countries (e.g. many countries of Africa, Asia, and South and Central America) where access to clean water and basic sanitation is lacking. Nearly all children in this setting will acquire Giardia at some point in their childhood, and the prevalence of the parasite in young children can be as high as 10%-30%. In areas such as Western Europe and the United States of America, Giardia infection is associated with ingestion of contaminated water, person-to-person spread, recent foreign travel, and recreational swimming. Giardia may be a cause of 2%-5% of cases of diarrhoea in high-income countries.
The Crypto-Giardia Device is a qualitative immunoassay for the detection of Cryptosporidium and Giardia antigen in human faeces samples. The membrane is pre-coated with antibodies against Cryptosporidium (red line) and antibodies against Giardia (blue line) antigens on the test line region. During testing, the sample reacts with the particle coated with anti-Cryptosporidium and anti-Giardia antibodies which was pre-dried on the test strip. The mixture moves upward on the membrane by capillary action. In the case of a positive result the specific antibodies present on the membrane will react with the mixture conjugates and generate one or two coloured lines. A green coloured band always appears in the control line (third line) and serves as verification that sufficient volume was added, that proper flow was obtained and as an internal control for the reagents.
- For professional in vitro diagnostic use only.
- Do not use after expiration date.
- The test should remain in the sealed pouch until use.
- Do not use the test if pouch is damaged.
- Follow Good Laboratory Practices, wear protective clothing, use disposal gloves, do not eat, drink or smoke in the area.
- All the specimens should be considered potentially hazardous and handled in the same manner as an infectious agent.
- The test should be discarded in a proper biohazard container after testing.
- The test must be carried out within 2 hours of opening the sealed bag.
Storage and stability
Store as packaged in the sealed pouch either at refrigerated or room temperature (2-30ºC/36-86ºF). The test is stable through the expiration date printed on the sealed pouch. The test must remain in the sealed pouch until use. Do not freeze
- Instructions for use
- Specimen collection vial with buffer
Materials required but not provided
- Specimen collection container
- Disposable gloves
Specimen collection and preparation
Collect sufficient quantity of faeces (1-2 g or mL for liquid sample). Stool samples should be collected in clean and dry containers (no preservatives or transport media). The samples can be stored in the refrigerator (2-4ºC/36-40ºF) for 1-2 days prior to testing. For longer storage the specimen must be kept frozen at -20ºC/-4ºF. In this case, the sample will be totally thawed, and brought to room temperature before testing.
Make sure that specimens are not treated with solutions containing formaldehyde or its derivatives.
To process the collected stool samples (see illustration 1):
Use a separate specimen collection vial for each sample. Unscrew the cap of the vial and introduce the stick two times into the faecal specimen to pick up a little of sample (150 mg) .
Close the vial with the buffer and stool sample. Shake the vial in order to assure good sample dispersion. For liquid stool samples, aspirate the faecal specimen with a dropper and add 150 uL into the specimen collection vial with buffer.
Test Procedure (see illustration 2)
Allow the tests, stool samples and buffer to reach to room temperature (15-30ºC/59-86ºF) prior to testing. Do not open pouches until ready to perform the assay.
- Remove the Crypto-Giardia Device from its sealed pouch and use it as soon as possible.
- Shake the specimen collection vial to assure a good sample dispersion. Break off the tip of the vial.
- Use a separate device for each sample. Dispense exactly 4 drops into the specimen well (S). Start the timer.
- Read the result at 10 minutes after dispensing the sample.
Interpretation of results
CRYPTO positive: Two lines appears across the central window, in the result line region (red test line marked in the illustration 3 with the letter T) and in the control line region (green control line marked in the illustration 3 with the letter C).
GIARDIA positive: Two lines appears across the central window, in the result line region (blue test line marked with the letter T) and in the control line region (green control line marked with the letter C). See illustration 3.
CRYPTO-GIARDIA positive: Three lines appears across the central window, in the result line region two lines (red test line and blue test line marked with the letter T) and in the control line region (green control line marked with the letter C). See illustration 3.
NEGATIVE: Only one green band appears across the control line region marked with the letter C (control line). See illustration 3.
INVALID: A total absence of the green control coloured band regardless the appearance or not of the red and blue test lines. Note: Insufficient specimen volume, incorrect procedural techniques or deterioration of the reagents are the most likely reasons for control line failure. Review the procedure and repeat the test with a new test. If the problem persists, discontinue using the test kit and contact you local distributor. See illustration 3.
Notes on the interpretation of results
The intensity of the red and blue coloured band in the result line region (T) will vary depending on the concentration of antigens in the specimen. However, neither the quantitative value, nor the rate of increase in antigens can be determined by this qualitative test.
Internal procedural controls are included in the test:
- A green line appearing in the control line region (C). It confirms sufficient specimen volume and correct procedural technique.
- Crypto-Giardia Device will only indicate the presence of parasites in the specimen (qualitative detection) and should be used for the detection of Cryptosporidium and Giardia antigens in faeces specimens only. Neither the quantitative value nor the rate of increase in antigen concentration can be determined by this test.
- An excess of sample could cause wrong results (brown bands appear). Dilute the sample with the buffer and repeat the test.
- Do not use specimens treated with solutions containing formaldehyde or its derivatives.
- If the test result is negative and clinical symptoms persist, additional testing using other clinical methods is recommended. A negative result does not at any time preclude the possibility of cryptosporidiosis or giardiasis.
- After one week of infection, the number of parasites in faeces is decreasing, making the sample less reactive. Stool samples should be collected within one week of the onset of symptoms.
- This test provides a presumptive diagnosis of cryptosporidiosis and/or giardiasis. All results must be interpreted together with other clinical information and laboratory findings available to the physician.
Cryptosporidium has caused several large waterborne disease outbreaks of gastrointestinal illness, with symptoms that include diarrhea, nausea, and/or stomach cramps. People with severely weakened immune systems (that is, severely immunocompromised) are likely to have more severe and more persistent symptoms than healthy individuals.
Giardia is prevalent throughout the world, including temperate, high-income countries, such as the UK and the United States. Several studies have examined acquisition of giardiasis in international travellers.
Sensitivity and specificity
It was studied some stool samples (determined by microscopy techniques) from patients in a local Hospital in Spain. The result showed using Crypto-Giardia Device:
>99% of sensitivity for Cryptosporidium and >99%of sensitivity for Giardia
>99% of specificity for Cryptosporidium and >99% of specificity for Giardia
The samples were tested with microscopy technique.
It was performed an evaluation to determine the cross reactivity of Crypto-Giardia Device. There is not cross reactivity with common gastrointestinal parasites occasionally present in feces.
- Hill DR, Nash TE. Intestinal Flagellate and Ciliate Infections. In: Guerrant RL, Walker DH, Weller PF, eds. Tropical Infectious Diseases. Principles, Pathogens & Practice. 2nd ed. Elsevier, Philadelphia. 2006:984-8.
- Copue S, Delabre K, Pouillot R et al. Detection of Cryptosporidium, Giardia and Enterocytozoon bieneusi in surface water, including recreational areas: a one year prospective study: FEMS Immunol Med Microbiol. 2006; 47:351-9.
- Stuart JM, Orr HJ, Warburton FG, et al. Risk Factors for Sporadic Giardiasis: A Case-Control Study in Southwestern England. Emerg. Infect Dis. 2003; 9, 2