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PREGNANCY TEST

PRINCIPLE

Human Chorionic Gonadotropin (hCG) is secreted by the developing placenta shortly after fertilization and can be detected before the first missed menses. The Sure-Vue™ hCG test is an immunoassay which uses serum or urine to detect hCG. Specimen is placed in test sample well. The sample migrates by capillary action along a membrane which is impregnated with monoclonal mouse-hCG specific antibody and colored conjugate. A positive specimen reacts with the antibody-conjugate complex and forms a red colored line in the T (test) window. Absence of this colored line indicates a negative result. A red colored line in the C (control) window serves as a control for the procedure and appears for all samples.

 

CLINICAL UTILITY

HCG detection is most often used to confirm pregnancy.

 

SPECIMEN

1. Type: Urine
2. Sample size: 150 uL. (four drops)
3. Store refrigerated at 2-8°C up to 72 hours or below -20°C for three months.

 

LIMITATIONS

1. Diluted urine specimens with low specific gravity may not contain enough hCG for detection. If pregnancy is still suspected, a first morning specimen should be obtained.
2. A number of conditions other that pregnancy, including trophoblastic disease and certain nontrophoblastic neoplasms, cause elevated levels of hCG. These diagnoses should be considered if appropriate to the clinical evidence.

 

SENSITIVITY

Sensitivity: Assay will detect urine hCG concentrations of 25 mIU/mL or greater.

 

SPECIFICITY

Specificity: 100%

 

COMPUTER CODES

Order Code: PRGU
Workcenter: 262
Testing site: 263

 

QUALITY CONTROL For the following locations that obtain hCG packs directly from Chemical Pathology: MOTT OR, MAIN OR, ADS, KELLOGG OUTPATIENT SURGERY:

Quality Control is performed by Chemical Pathology personnel daily
on the packs issued to these units.

 

PROCEDURE Test kits, specimens, and controls must be at room temperature prior to testing.

1. Remove test cartridge from pouch. Label cartridge with sample ID.

2. Dispense 4 drops of specimen (approximately 0.15 mL) into the round sample well. Wait for colored lines to appear.

3. Read results after 4 minutes and no later than 30 minutes. Weak positive samples may take a full 4 minutes to show a line in the test window. Positive results may be accepted as soon as control line is visible.

NOTE: If no colored line appears in control window add two more drops of urine and wait 4 more minutes.

 

INTERPRETATION AND REPORTING NEGATIVE
The test is negative if a colored line appears only in the C (control) window.

POSITIVE
The test is positive if a colored line appears in the T (test) window and a colored line appears in the C (control) window. Any intensity colored line in the T (test) window should be considered positive. Colored lines may be lighter or darker than each other.

INVALID RESULT
The test is invalid if no colored line appears in the C (control) window, even if a colored line appears in the T (test) window.

QUESTIONABLE SPECIMENS are those which show a barely detectable verical T (test) line. Report as Questionable Negative. Recommend repeating pregnancy test in 48 hours if “Questionable Negative” or on the first morning specimen.

 

MATERIALS AND REAGENTS Sure-Vue™ hCG test kits contain 50 individually sealed test cartridges with disposable pipets. Test cartridges contain monoclonal mouse-hCG colored conjugate and hCG antibody coated on a membrane.

Store test packs at room temperature until expiration date listed on kits.

 

REFERENCES

1. 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 31:1322-28, 1985.

2. 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.

3. Sure-Vue™ Serum/Urine hCG product insert., Fisher Scientific Company, April 1999.

 

METHODOLOGY HISTORY

REVISED BY
DATE
COMMENTS
DMH 11/23/99 New Procedure - Sure-Vue™ Qualitative Serum/Urine hCG (Replaces Abbott Combo +Plus™)
DXT 12/1/99 Modified Quality Control Section
     
     
     
     
     
     
     
     
     
     
     
     

 

 

 


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