Storage and Stability

Store at room temperature (15° to 30°C / 59° to 86°F). The test device must remain in the foil pouch until ready for use. Sealed pouches are good until the expiration date listed on the pouch.

Precautions

1. Test devices should remain in the sealed pouch until ready for use.
2. All specimens should be considered potentially hazardous and handled in the same manner as an infectious agent.
3. The test device should be discarded in a proper biohazard container after testing.
4. Do not use test kit beyond the expiration date.

Specimen Collection and Preparation

Urine specimens should be collected in a clean, dry container. Randomly collected specimens can be used. However, the first morning urine generally contains the highest concentration of hCG. If urine samples exhibit visible precipitates, the specimen should be filtered, centrifuged, or allowed to settle to obtain clear aliquots.

Specimen Storage

Specimens may be refrigerated (2° - 8°C) and stored up to 72 hours prior to assay. If specimens are refrigerated, they must be brought to room temperature before testing. If testing is delayed more the 48 hours, the specimens should be frozen. Frozen specimens should be thawed and mixed before testing.

Directions For Use

Allow specimen and/or controls to reach room temperature (15°C to 30°C) prior to testing.
1. Remove the test device from the sealed pouch and place it on a level, dry surface.
2. Dispense 3 drops (approx. 0.12ml) of the urine specimen into the sample well. Wait for colored lines to appear.
3. Read results after 3 minutes. Some positive results may be observed in 60 seconds or less depending on the concentration of hCG. Specimens containing levels of hCG below 20mIU/ml may show color development over time, therefore, do no read results after 10 minutes.

Interpretation of Results

Negative Results

The test is negative if only one colored line appears in the Control Zone. This indicates the absence of detectable levels of hCG.

Positive Results

The test is positive if two colored lines appear. One colored line will appear in the Test Zone and one in the Control Zone. This indicates the specimen contains detectable levels of hCG. Any colored line in the Test Zone should be considered positive. Specimens containing levels of hCG below 20 mIU/ml may show color development over time. The colored line in the Control Zone may be lighter or darker in color than the line in the Test Zone.

Invalid Results

The test is invalid if a colored line fails to appear in the Control Zone, even if a colored line appears in the Test Zone. If this occurs, add 2 additional drops of specimen and wait 3 minutes. If a colored line still does not appear in the Control Zone, the test is invalid and should be repeated with a new test device.

Limitations

1. A number of conditions other than pregnancy may produce elevated levels of hCG such as trophoblastic disease, choriocarcinoma, embryonal cell carcinoma, Islet cell tumors, and other carcinomas.4
2. If urine specimens are too dilute, false negative results may occur due to low levels of hCG below the sensitivity of the test. If pregnancy is still suspected, a first morning urine should be collected 48 hours later and tested.
3. False positive results may be due to detectable levels of hCG remaining several weeks after a normal pregnancy, delivery by cesarian section, spontaneous or therapeutic terminations.5
4. Very low levels of hCG may be found in ectopic pregnancies6 and additional testing may be necessary using a quantitative assay.
5. Natural termination occurs in 22% of clinically unrecognizable pregnancies, and 31% of pregnancies overall.7 This may produce positive results when testing early in the pregnancy followed by negative results after the natural termination. In cases exhibiting weak positive results, it is good laboratory practice to confirm results by retesting with a first morning urine 48 hours later.
6. All clinical and laboratory findings should be evaluated before making a definitive diagnosis.

 
 

REFERENCES

1. Braunstein GD, Rasor J, Adler D, Danzer H, Wade ME: Serum human chorionic gonadotropin levels through normal pregnancy. Am J Obstet Gynecol, 126: 678-681, 1976.
2. Schwartz S, Berger P, and Wick G: Epitope-selective monoclonal antibody based immunoradiometric assay of predictable specificity for differential measurement of choriogonadotropin and its subunits, Clin Chem 31:1322- 1328, 1985.
3. Kaplin LA, Pesce AJ. Clinical Chemistry Theory, Analysis, & Correlation, 2nd Edition, Missouri, 1989, C.V. Mosby Co., p. 944.
4. Jacobs DS, et al: Laboratory Test Handbook, 2nd Edition, Ohio, Lexi-Comp Inc., pp. 224, 305-307, 1990.
5. Steier JA, Bergso p, Myking OL: Human chorionic gonadotropin in maternal plasma after induced abort., spontaneous abortion, and removed ectopic pregnancy. Obstet Gynecol 64: 391-394, 1984.
6. Thorneycroft IH: When you suspect ectopic pregnancy. Diagnosis January: 67-82, 1976.
7. Wilcox EG, Weinberg CR, O'Connor JF, et al: Incidence of early loss of pregnancy. N Eng J Med 319: 189-194, 1988.
8. Chard T, Pregnancy Tests: A Review. Human Reproduction, 7:701-710, 1992.