Womens Health

dBest One Step Urine Test

Pregnancy Test Strip
For Urine
(Revised October 2000)

Intended Use

The dBest One Step hCG Urine Test is an immunoassay designed for the qualitative determination of the human chorionic gonadotropin (hCG) in urine for the early detection of pregnancy. It is intended for professional or laboratory use.

Summary and Explanation of the Test

Human chorionic gonadotropin (hCG) is a glycopeptide hormone produced by the placenta during pregnancy. The appearance and rapid increase in the concentration of hCG in the mother's urine makes it a good marker for confirming pregnancy. The concentration of hCG in urine increases steadily to a circulation peak of as much as 50,000 mIU/ml between the eighth and eleventh weeks (1,2,3).

The dBest One Step hCG Urine Test is a chromatographic immunoassay which use specific antibodies to selectively identify hCG in urine with a high degree of sensitivity. Elevated levels of hCG as low as 20 mIU/ml can be detected within 3 minutes.

Principles of the Test

Urine is added to the test kit and allowed to migrate through the absorbent device. The labeled antibody-dye conjugate binds to the hCG in the specimen forming an antibody-antigen complex. This complex binds to the anti-hCG antibody in the test zone and produces a purple color band when the hCG concentration is equal to or greater than 20 mIU/ml. In the absence of hCG, no band is formed in the test zone. The reaction mixture continues flowing through the absorbent device past the test and control zones. Unbound conjugate binds to the reagents in the control zone, producing a purple color band, demonstrating that the reagents and the test kit are functioning correctly.

Reagents Used

For in vitro diagnostic use only. The test kit contains combination of goat/rabbit polyclonal antibodies and mouse monoclonal antibodies in a protein buffer containing sodium azide.

Precautions

(1) For in vitro diagnostic use only.

(2) Do not use after the expiration date imprinted on the test kit package.

(3) Dispose of all reaction devices in a proper biohazard container.

(4) Patient specimens may contain infectious agents and should be handled as potential pathogens.

Test Kit Storage

The test kit may be stored at room temperature for up to 18 months or until the expiration date. Optional Liquid control reagent may have different storage requirements. Refer to individual components for their specific requirements.

Urine Collection and Storage

(1) First morning urine typically contains the highest concentration of hCG and is therefore the best sample for performing the urine test. However, any urine specimen may be used.

(2) Collect the urine specimen in a clean glass or plastic container. Do not use preservatives.

(3) If the specimen is not used immediately following collection, but is to be used within 48 hours it should be refrigerated (2 to 8 degrees C), and brought back to room temperature (l5 to 30 degrees C) before testing. If specimen is not going to be used for more than 48 hours, it should be frozen at -20 degrees C. A frozen specimen should not be used if stored longer than 2 weeks. Prior to testing, the frozen specimen must be completely thawed, thoroughly mixed, and brought to room temperature.

Assay Procedure

1. Remove the test strip from its foil pouch.

2. Holding the strip vertically, carefully dip it into the specimen. Do not immerse the strip past the maximum line (Figure 1).

3. The strip can be left in the specimen or can be removed from the specimen when red-dye begins to migrate through the Result Window. Interpret test results at 3 to 5 minutes. Do not interpret test results after 5 minutes.

Interpretation of Results

(1) NEGATIVE: If there is only one purple color band in the result window, this indicates that the specimen does not contain a detectable level of hCG and should be interpreted as a negative result (Figure 2).

(2) POSITIVE: If there are two purple color bands in the result window, this indicates that the specimen contains hCG and should be interpreted as positive result (Figure 2).

(3) INVALID: If there is no purple color bands in the result window, the test result is invalid. The control band will not appear if an insufficient volume of specimen is added into the test kit. Proper procedures may not have been followed in performing the test or deterioration of the test kit may have occurred. Repeat the test procedure using a new test kit.

Note: The instructions provided must be strictly followed in order to achieve optimal test reactivity with the urine specimens.

Limitations of the Procedure

1. The dBest Urine hCG Pregnancy Test is for in vitro diagnostic use only.

2. In addition to pregnancy, hCG has been found in patients with both gestation and non-gestation trophoblastic diseases. These conditions should be ruled out when interpreting hCG levels to establish a pregnancy diagnosis.

3. Although the test is very accurate in detecting pregnancy a low incidence of false results can occur. Consult with a physician if unexpected or inconsistent results are obtained.

4. A normal pregnancy cannot be distinguished from an ectopic pregnancy based solely on hCG levels. Also, a spontaneous miscarriage may cause confusion in interpreting test results.

5. As with all diagnostic tests, a definitive clinical diagnosis should not be based on the results of a single test, but should only be made by the physician after all clinical and laboratory findings have been evaluated.

6. A negative result obtained from a urine specimen collected from a mother in very early pregnancy may be due to an extremely low concentration of hCG. In such cases, the test should be repeated on a fresh specimen obtained two days later.

7. If a urine sample is too dilute (i.e. low specific gravity), it may not contain a representative urinary hCG concentration. If a negative result is obtained with a low specific gravity specimen and pregnancy is still suspected, obtain a first morning urine specimen and retest.

8. These pregnancy test strips selectively identify hCG in the urine with a high degree of sensitivity. Testing should NOT begin before day 12 after ovulation or two days before expected menses. This is because on the average, implantation does not take place until day 8 after ovulation.

9. If you begin testing before a missed menses you may sometimes have a positive test that subsequently turns negative and your menses comes on time or up to several days to a week or two late. This may represent a subclinical (chemical) pregnancy. We know that up to 25% of all pregnancies are merely chemical pregnancies that do not continue when sensitive quantitative serum (blood) HCG tests are performed (1).

 

Expected Normal Values

Urine hCG levels during pregnancy are estimated to be (1,2,3):
1. 10-30 mIU/ml 7-10 days post conception.
2. 37,000-50,000 mIU/ml 8-11 weeks after last menstrual period.
3. <5 mIU/ml Healthy men or non-pregnant women.

Standardization

The dBest Pregnancy Urine Test will detect hCG concentrations of 20 mIU/ml or greater (referenced to the World Health Organization First International Standard).

Performance Characteristics

Sensitivity

The dBest Pregnancy Urine Test will detect hCG in urine at concentrations of 20 mlU/ml or greater. This sensitivity level has been confirmed with interval hCG standards in urine, calibrated against the World Health Organization First International Standard.

Specificity

The ability of the dBest Urine hCG Pregnancy Test to specifically detect hCG was challenged through cross-reaction studies on urine samples containing known quantities of structurally and physiologically related hormones. Urine samples spiked with 500mIU/ml LH (human Luteinizing Hormone), 1000 mIU/ml FSH (Follicle Stimulating Hormone), 1000 mIU/ml TSH (Thyroid Stimulating Hormone) show negative results only.

Interference Data

Potentially interfering drugs, protein and glucose were supplemented to normal urine specimens devoid of hCG, Baseline urine level, as well as 20 mIU/ml hCG standards were then analyzed and compared with all samples containing a specific concentration of an interfering substance.

Substances

Acetaminophen, 20 mg/dl
Acetylsalicylic acid, 20 mg/dl
Ascorbic acid, 20 mg/dl
Atropine, 20 mg/dl
Caffeine, 20 mg/dl
Gentistic acid, 20 mg/dl
Glucose, 2000 mg/dl
Hemoglobin, 500 mg/dl
Mestranol, 3 mg/dl
Penicillin, 40,000 U/dl
Tetracycline, 20 mg/dl

Conclusion: All of the above substances have no interference with the results of "dBest" urine test kits.

Accuracy

1. The dBest hCG Urine test compared with a commercially available urine tests (Table).

  A commercial urine test
    Negative Positive Total
dBest
urine
test
Negative 50 0 50
Positive 0 50 50
Total 50 50 100

 

The conclusion is the dBest hCG Urine strip format is comparable with a commercially available urine test.

References

1. E.A. Lenton, LM. Neal, and Sulaiman. R. Fertil, Steril., Vol. 37 (1982), p773.

2. E. F. Batzer. Fertil, Steril., Vol. 34 (1980), p1.

3. N. W. Tietz. Clinical Guide to Lab. Tests, 2nd ed., p128, 1990.

AmeriTek, Inc.
Seattle, Washington, USA
Telephone 206-527-5086
Fax 206-528-8107

R04-110hCG

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