PYtest by is a Prescription medication manufactured, distributed, or labeled by Avent, Inc.. Drug facts, warnings, and ingredients follow.
PYtest1 (14C-urea capsules) is intended for use in the detection of gastric urease as an aid in the diagnosis of Helicobacter pylori (H. pylori) infection in the human stomach. The test utilizes a liquid scintillation counter for the measurement of 14CO2 in breath samples. The capsules are to be used when analysis is planned at the site where the sample is taken.
PYtest1 capsule is a gelatin capsule for oral administration containing 1 µCi of 14C labeled urea. The urea is adsorbed on sugar spheres and colored yellow with fluorescein.
Structural Formula (14C-urea): NH2 14CONH2
Radiation emission: beta-emission, 49 keVmean, 156 keVmax, no other emissions
External emission: No external radiation hazard. Low-energy beta emissions only.
Maximum range of 0.3 mm in water.
Radiological Half-life: 5730 years
Maximum effective dose equivalent (EDE) : 0.3 mrem/µCi
The urease enzyme is not present in mammalian cells, so the presence of urease in the stomach is evidence that bacteria are present. The presence of urease is not specific for H. pylori, but other bacteria are not usually found in the stomach. The principle of the breath test is shown in Figure 1.
Figure 1: Principle of Breath Test
To detect H. pylori, urea labeled with 14C is swallowed by the patient. If gastric urease from H. pylori is present, urea is split to form CO2 and NH3 at the interface between the gastric epithelium and lumen and 14CO2 is absorbed into the blood and exhaled in the breath.
Following ingestion of the capsule by a patient with H. pylori, 14CO2 excretion in the breath peaks between 10 and 15 minutes and declines thereafter with a biological half-life of about 15 minutes. 14C-urea that is not hydrolyzed by H. pylori is excreted in the urine with a half-life of approximately 12 hours. About 10% of the 14C remains in the body at 72 hours and is gradually excreted with a biological half-life of 40 days.
Two studies were performed. In both studies, patients with gastrointestinal symptoms underwent the breath test and an endoscopy. During the endoscopy, biopsy samples were taken from the antral gastric mucosa for histological analysis (2 samples, Giemsa stain) and rapid urease test (1 sample, CLOtest1). Breath samples were mailed to the TRI-MED lab where they were read in a liquid scintillation counter.
Results were reported as disintegrations per minute (DPM). Analysis for accuracy used the ten minute breath sample. A breath sample DPM <50 was defined as a negative result. DPM ≥ 200 was defined as a positive result. DPM in the range of 50–199 was classified as indeterminate.
Of 186 patients who had histopathology and CLOtest1 (80 men, 106 women), 53 were infected with H. pylori as determined by agreement between histology and CLOtest1. The study results are summarized below:
Histology and CLOtest1 | ||||||
---|---|---|---|---|---|---|
H. pylori | Positive | Negative | Total | |||
Notes: PYtest1 at 10 min. was compared to the gold standard of biopsy results in which histology and CLOtest1 concurred. Patients who did not have both biopsy tests performed, or in whom the tests differed, were excluded from analysis. There was no statistical difference in test accuracy based on gender of patient. | ||||||
ppv = positive predictive value (true positive divided by total PYtest1 positive) | ||||||
npv = negative predictive value (true negative divided by total PYtest1 negative) | ||||||
PYtest1 | Positive | 51 | 8 | 59 | ppv. | 86% |
(DPM | Indeterminate | 1 | 8 | 9 | ||
10 min.) | Negative | 1 | 117 | 118 | npv. | 99% |
Total | 53 | 133 | 186 | |||
sensitivity | specificity | |||||
96% | 88% |
Breath tests were performed on 436 outpatients attending gastroenterology practices at sites in the United States. Seventy-six patients (40 men, 36 women) who had histology and CLOtest1 were evaluated. The results are summarized below:
Histology and CLOtest1 | ||||||
---|---|---|---|---|---|---|
H. pylori | Positive | Negative | Total | |||
Notes: PYtest at 10 min. was compared to the gold standard of biopsy results in which histology and CLOtest concurred. Patients who did not have both biopsy tests performed, or in whom the tests differed, were excluded from analysis. There was no statistical difference in test accuracy based on gender of patient. | ||||||
ppv = positive predictive value (true positive divided by total PYtest1 positive) | ||||||
npv = negative predictive value (true negative divided by total PYtest1 negative) | ||||||
PYtest1 | Positive | 22 | 0 | 22 | ppv. | 100% |
(DPM | Indeterminate | 4 | 2 | 6 | ||
10 min.) | Negative | 1 | 47 | 48 | npv. | 98% |
Total | 27 | 49 | 76 | |||
sensitivity | specificity | |||||
82% | 96% |
PYtest1 (14C-Urea breath test) is indicated for use in the detection of gastric urease as an aid in the diagnosis of H. pylori infection in the human stomach. The test utilizes a liquid scintillation counter for the measurement of 14CO2 in breath samples.
After the patient ingests the 14C-urea capsule, the sample collected for test purposes is for in vitro diagnostic use only.
A false positive test could occur in patients who have achlorhydria. Very rarely, a false positive test may occur due to urease associated with Helicobacters other than H. pylori (i.e. Helicobacter heilmanni).
Persons concerned about very low doses of radioactivity may postpone the test or may decide to use an alternative means of diagnosis. The test produces radiation exposure equal to 24 hours of normal background. In animal experiments, such low doses of radiation do not carry measurable risk.
Preclinical studies were not conducted on 14C-urea. The estimated dose equivalent received from a single administration of PYtest1 (1 µCi 14C) is about 0.3 mrem.
It is necessary for the patient to fast for 6 hours before the test. The patient should also be off antibiotics and bismuth for 1 month, and proton pump inhibitors and sucralfate for 2 weeks prior to the test. Instruct the patient not to handle the capsule directly as this may interfere with the test result. The capsule should be swallowed intact. Do not chew the capsule.
No studies have been conducted with 14C-urea to evaluate its potential for carcinogenicity, impairment of fertility, or mutagenicity.
Antibiotics, proton pump inhibitors, sucralfate, and bismuth preparations are known to suppress H. pylori. Ingestion of antibiotics or bismuth within 4 weeks and proton pump inhibitors or sucralfate within 2 weeks prior to performing the test may give false negative results.
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when PYtest1 is administered to a nursing woman.
Clinical studies in children have not been conducted. However, PYtest1 is expected to work the same in children as in adults. While the dose (1 capsule) does not need to be adjusted, the child must be able to swallow the intact capsule and blow into a straw.
FOR ANALYSIS AT TEST SITE
BREATH SAMPLE COLLECTED INTO BALLOON
(RECOMMENDED METHOD; SEE FIGURE 2)
FOR ANALYSIS ON SITE
BREATH SAMPLE COLLECTED INTO VIAL
CAUTION: Kimberly-Clark does not endorse breath sample collection by this method because patients might come into direct contact with the hyamine.
Figure 3: Typical Safety Trap
One PYtest1 capsule.
Before the test |
|
Minus 1 minute |
|
0 minute |
|
3 minutes | Ask the patient to drink another 20 ml of lukewarm water (in case the capsule may have lodged in the esophagus and not yet reached the gastric mucosa). |
10 minutes |
|
After sample collection | See test analysis procedure. |
CAUTION: Kimberly-Clark does not endorse the collection of breath samples by this method for patient safety reasons. | |
Before the test |
|
Minus 2 minutes | Attach a straw to the safety trap (Figure 3). |
Minus 1 minute |
|
0 minute |
|
3 minutes | Ask the patient to drink another 20 ml of lukewarm water (in case the capsule may have lodged in the esophagus and not yet reached the gastric mucosa). |
10 minutes | Ask the patient to hold his/her breath for 5–10 seconds, then blow bubbles into the collection fluid via the safety trap. The patient should blow bubbles until the fluid turns clear. Put lid on vial. |
After sample collection | See test analysis procedure. |
BALLOON READ ON-SITE:
VIALS READ ON-SITE
See steps 12–14 under "Balloon read on-site."
A minimum of 1 mmol of CO2 is required to perform analysis of a breath sample. The amount of breath required to provide 1 mmol of CO2 varies depending on the amount of CO2 the patient is producing. Since a full balloon typically contains at least 1 mmol of CO2, the balloon should be completely filled.
Interpretation of results (10 minute sample) | |
< 50 DPM | Negative for H. pylori |
50–199 DPM | Indeterminate for H. pylori |
≥ 200 DPM | Positive for H. pylori |
The indeterminate result should be evaluated by repeating the PYtest1 or using an alternative diagnostic method. If repeat breath testing is undertaken, careful history to exclude confounding factors should be obtained. If confounding factors are identified, wait an appropriate time (refer to table 3) before repeating the PYtest1.
The cutoff point of 50 DPM was determined to be the mean +3SD of results obtained in patients who did not have H. pylori.
DPM = Disintegrations per minute
Factor | Result | Comment |
---|---|---|
Recent antibiotic or bismuth (Pepto-Bismol, etc.) | false neg. | Relapse of partially treated Hp may take 1–4 weeks. |
Omeprazole (or other proton pump inhibitors) | false neg. | These agents suppress Hp in 40% of patients. Discontinuefor at least 2 weeks before performing the PYtest1. |
Resective gastric surgery | false neg. | Isotope may empty rapidly from the stomach. |
Resective gastric surgery | false pos. | Patient may be achlorhydric and have bacterial overgrowth (non-Hp urease). |
Food in stomach (also bezoar, gastroparesis) | unknown | Isotope may not come into contact with gastric mucosa Patient may be achlorhydric and/or have bacterial overgrowth (non-Hp urease). |
As shown in Figure 4 approximately 30% of patients tested will be positive for H. pylori.
Figure 4: Histogram showing DPM distribution for the PYtest1.
*Note: DPM groupings were calculated on a logarithmic scale. Empty DPM groupings were not included. Chart includes all patients from Studies 1 and 2. Frequency of DPM group includes samples with DPM < Group Name.
If the capsule is damaged or appears abnormal in any way, it may give inaccurate results.
Kimberly-Clark | Distributed in the U.S. by Kimberly-Clark Global Sales, LLC, Roswell, GA 30076 USA In USA, please call 1-800-KCHELPS www.kchealthcare.com Kimberly-Clark, Roswell, GA 30076 USA Kimberly-Clark N.V., Belgicastraat 13, 1930 Zaventem, Belgium Sponsored in Australia by Kimberly-Clark Australia Pty Limited; 52 Alfred Street Milsons Point, NSW 2061 1-800-101-021 |
©2003 KCWW. All rights reserved. 14-63-133-0-00/70080916 |
AVANOS*
PYtest*
14C-UREA BREATH TEST CAPSULES
FOR THE DETECTION OF HELICOBACTER PYLORI
Contents – 10 PYtest* Capsules each containing 1 µCi 14C-Urea
For dosage information, please see package insert
14C-Urea (5730 years1/2, 156 keV[max.] β-emission)
NDC: 42536-6044-2
For In Vitro
Diagnostic Use
Rx Only
Store at
15°–30°C
(59°–86°F)
REF
60442
PYTEST
urea, c-14 capsule |
||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||
|
Labeler - Avent, Inc. (049316284) |
Establishment | |||
Name | Address | ID/FEI | Business Operations |
---|---|---|---|
Avent, Inc. | 049316284 | api manufacture(42536-6044) |
Mark Image Registration | Serial | Company Trademark Application Date |
---|---|
![]() PYTEST 76395324 2674966 Live/Registered |
AVENT, INC. 2002-04-15 |