H. Pylori Stool Antigen Test is an in vitro qualitative immunochromatographic assay for the rapid detection of Helicobacter Pylori antigens present in the human stool specimen. The test results are intended to diagnose H. Pylori (Ag) infection and monitor the effectiveness of the therapeutic treatment and to confirm the eradication of infection in the peptic ulcer patients.
H. Pylori (Helicobacter Pylori) is a corkscrew-shaped, gram-negative rod that lives in the mucous layer of the stomach. H. Pylori infection is now accepted as the most common cause of gastritis and is etiologically involved in the gastric ulcer, gastric adenocarcinoma, duodenal ulcer, and primary gastric B-cell lymphoma. The organism is very common and has infected at least half of the world’s population. H. Pylori infection is typically acquired in childhood and once acquired; this infection persists chronically, probably continuing in the stomach throughout life. The damage done to the gastric structure and functioning of the stomach is constant and direct.
Approximately one in six of H. Pylori infection can develop peptic ulcer disease and a small portion can lead to gastric cancer. The diagnostic tests for this can be classified into two categories, invasive and noninvasive tests. Direct detection by invasive test procedure requires an endoscopy and biopsy specimens from antrum and stomach body. The presence of H. Pylori is then confirmed by the direct culture, histological examination or rapid urease test. The endoscopy and biopsy specimens directly detect active H. Pylori infections. Although the procedure is highly specific and high positive predictive value, the cost and discomfort to the patients are also very high.
The most widely available noninvasive test is probably the serological based test, it detects H. Pylori specific IgG antibody in the patient’s serum with current or prior infection. Serology test is a simple, convenient test with relatively high sensitivity. The main limitation of this serology test is the inability to distinguish the current and past infections. An antibody may be present in the patient's serum long after the eradication of the organism.
The Urease breath test (UBT) with 14C or 13C labeled urea, is a noninvasive test based on the urease activity of the organism.UBT detects active H. Pylori infection and is highly sensitive and specific. This test requires high density and active bacteria and should not be performed until 4 weeks after the therapy to allow residual bacterial to increase to a sufficient number for detection. H. Pylori Ag Rapid Test is a sandwich solid phase immunochromatographic assay that uses antibody coated colloidal-gold to detect the presence of H. Pylori antigens in the stool specimens. The test is simple and easy to perform and the results can be interpreted within 15 minutes.
PRINCIPLE OF THE ASSAY
To perform the test, an aliquot of the diluted stool sample should be added to the sample well of the test cassette. The sample then flows through the label pad containing H. Pylori antibody coupled to red-colored colloidal-gold. If the sample contains the antigens, it will bind to the antibody coated on the colloidal-gold particles to form antigen-antibody-gold complexes. These complexes then move on the nitrocellulose membrane by capillary action toward the test line region on which H. Pylori specific antibodies are immobilized. As the complexes reach the test line, they bind to the antibody on the membrane and form a line. A second red control line will appear in the result window to indicate that the test has been correctly performed and the device is functioning properly. If H. Pylori antigen is not present or lower in the limit then only control line will be visible. If the control line is not developed, then the test is invalid.
Test Cassette: 20 test / box, Test Strip: 50 tests / box
Sample collection tube with diluents 1ml ×20 for cassette, sample diluents 30ml×1 for strip
Product instruction: 1
PRECAUTION FOR USERS
Do not pipette reagents by mouth and smoking or eating should be avoided while performing assays
Wear gloves during the whole procedure and avoid reagents or specimen spilling-out
Wipe up the spills using 5 percent hypochlorite solution
Decontaminate all the liquids or solid wastes before deposing of
For in-vitro diagnostic use only
Must not use the test kit beyond its expiration date
Do not mix the components from kits with different lot number
Avoid microbial contamination of reagents
The specimens should be collected in the containers that do not contain any media; preservatives, animal serum or detergents as the presence of any of these may interfere with the HP Stool Ag Test. Specimens must be stored at 2 to 8°C for 3 days without interfering with the assay performance. For long-term storage, -20°C or colder temperature is recommended. Repeated freezing and thawing of specimens is not recommended and it may cause erroneous results. Do not store the specimens in self-defrosting freezers.
STORAGE AND STABILITY
The test kit can be stored at any temperature between 4 to 30°C, do not freeze. The stability of the kit under these storage conditions is of 24 months. Use the reagents as soon as possible after the kit is unpacked within 3 months.
Make sure the kit and samples are at room temperature (20 to 30°C) before use (approximately 30 minutes).
Remove the test cassette/strip from the sealed foil pouch and place the plate on a horizontal platform.
Bring all materials and specimens to room temperature at 8 to 30°C
H. Pylori Stool Antigen test Strip
Add 500μl diluents sample into the test tube.
Add proper specimens (S: 5 mm in diameter, L: 50μl) into the test tube to make the concentration of the solution up to 5% to 10% and mix thoroughly.
Add 100μl (2 to 3 drops) of diluted stool sample to the sample pad of test strip.
H. Pylori Stool Antigen test Cassette
Take a portion of sample (about 100mg) and insert the sterile swab into a stool sample.
Open the sample collection tube and then insert the swab into the tube containing assay diluents.
Swirl the swab for at least 10 times until the sample has been dissolved into the assay diluents and discard the swab after squeezing it against the wall of the tube and replace the cap.
Add 100μl (2 to 3 drops) of diluted stool sample to the sample well of the test card.
Read the result in 5 to 10 minutes and a strong positive sample can show result early.
Note: Results after 15minutes may not be accurate.
INTERPRETATION OF RESULTS
Negative: If there is no line in the test region it means negative and one pink line appear in the control line, shows that the test has been carried out correctly.
Positive: In addition to the pink colored control line, a distinct pink colored band also appears in the test region.
Invalid: No color in either regions shows procedural error or that the reagent has deteriorated. It is recommended that the test should be repeated using a new strip.
Following bacterial and viral strains were used to test the specificity of the test. Positive and negative stools were spiked with >1x108 organism/ml and tested by the kit. H. Pylori positive stool remained positive with the spiked organisms and negative stool remained negative.
The product is only for testing the HP antigen in stool.
The test kit cannot be used as a quantitative reagent.
The positive results should further be verified by the clinical information.
All high sensibility immunological tests are inevitable to no specificity and biological false positive results.
The negative results can be caused by the lower concentration of the antibody than the product analysis sensitivity.
Used for IVD only
Store at dry place once opened use within 9 weeks and do not mix different batches.
This test kit does not produce any biological safety problems, but dealing with the used reagent and sample as infectious substances may cause some
The thick samples can block the test card. Centrifuge or keep it standing, and test the supernatant.
Do not add too much sample otherwise it will cause erroneous results.