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pregnancy testAny test used to detect or confirm pregnancy; in early pregnancy, all PTs measure hCG, the developing placenta's principal hormone, which is detectable as early as 6 days after fertilization; in clinical laboratories, serum levels of hCG are quantified by ELISA or RIA; home testing kits are reliable, widely used, operate on the principle of agglutination, and have < 1% error rate Ref range Nonpregnant < 5 mIU/mL. See hCG, Estriol.
A major class of pregnancy tests is those using immunodiagnostic procedures. They are the hemagglutination inhibition test, which requires a sample of urine; radioreceptor assay, which requires blood from the patient; radioimmunoassay, which requires a blood sample; and monoclonal antibody determination, which requires a sample of urine. In general, these tests are accurate beginning the 40th day following the first day of the last menstrual period; the monoclonal antibody test is somewhat more sensitive. The reliability of the test methods increases as pregnancy continues.
Human Chorionic Gonadotropin
SpecimenSerum (1 mL) collected in a gold-, red-, or red/gray-top tube. Plasma (1 mL) collected in a green-top (heparin) tube is also acceptable.
|Conventional Units||SI Units (Conventional Units × 1)|
|Males and nonpregnant females||Less than 5 milli international units/mL||Less than 5 international units/L|
|Pregnant females by week of gestation:|
|2 wk||5–100 milli international units/mL||5–100 international units/L|
|3 wk||200–3,000 milli international units/mL||200–3,000 international units/L|
|4 wk||10,000–80,000 milli international units/mL||10,000–80,000 international units/L|
|5–12 wk||90,000–500,000 milli international units/mL||90,000–500,000 international units/L|
|13–24 wk||5,000–80,000 milli international units/mL||5,000–80,000 international units/L|
|26–28 wk||3,000–15,000 milli international units/mL||3,000–15,000 international units/L|
This procedure is contraindicated for
- Assist in the diagnosis of suspected HCG-producing tumors, such as choriocarcinoma, germ cell tumors of the ovary and testes, or hydatidiform moles
- Confirm pregnancy, assist in the diagnosis of suspected ectopic pregnancy, or determine threatened or incomplete abortion
- Determine adequacy of hormonal levels to maintain pregnancy
- Monitor effects of surgery or chemotherapy
- Monitor ovulation induction treatment
- Prenatally detect neural tube defects and trisomy 21 (Down syndrome)
- Choriocarcinoma (related to HCG-producing tumor)
- Ectopic HCG-producing tumors (stomach, lung, colon, pancreas, liver, breast) (related to HCG-producing tumor)
- Erythroblastosis fetalis (hemolytic anemia as a result of fetal sensitization by incompatible maternal blood group antigens such as Rh, Kell, Kidd, and Duffy is associated with increased HCG levels)
- Germ cell tumors (ovary and testes) (related to HCG-producing tumors)
- Hydatidiform mole (related to HCG-secreting mole)
- Islet cell tumors (related to HCG-producing tumors)
- Multiple gestation pregnancy (related to increased levels produced by the presence of multiple fetuses)
- Pregnancy (related to increased production by placenta)
Any condition associated with diminished viability of the placenta will reflect decreased levels.Ectopic pregnancy (HCG levels increase slower than in viable intrauterine pregnancies, plateau, and then decrease prior to rupture) Incomplete abortion Intrauterine fetal demise Spontaneous abortion Threatened abortion
- Drugs that may decrease HCG levels include epostane and mifepristone.
- Results may vary widely depending on the sensitivity and specificity of the assay. Performance of the test too early in pregnancy may cause false-negative results. HCG is composed of an α and a β subunit. The structure of the α subunit is essentially identical to the β subunit of follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone. The structure of the β subunit differentiates HCG from the other hormones. False-positive results can therefore be obtained if the HCG assay does not detect β subunit.
Nursing Implications and Procedure
Potential nursing problems
|Problem||Signs & Symptoms||Interventions|
|Spirituality (Related to potential or actual; fear of fetal death; loss of potential child)||Forgiveness; acceptance; anger at spiritual leaders; expressed feelings of hopeless, powerlessness; abandonment; refusals or inability to participate in spiritual activities (prayer); expresses feelings over lack of meaning with life or serenity||Encourage the verbalization of feelings in a safe, nonjudgmental environment; assess the desire for contact from associated spiritual leader; foster a supportive relationship with the patient and family; encourage a display of objects (spiritual, religious) that provide emotional relief; assess for expressions of hope|
|Fear (Related to possible loss of potential child; ineffective coping; unfamiliar therapeutic regime; unknown)||Expression of fear; preoccupation with fear; increased tension; increased blood pressure; increased heart rate; vomiting; diarrhea; nausea; fatigue; weakness; insomnia; shortness of breath; increased respiratory rate; withdrawal; panic attacks||Provide specific education related to pregnancy confirmation and identification of viability; provide specific information related to ongoing pregnancy; communicate with social services for needed support; ensure education is culturally appropriate; assist the patient and family to recognize effective coping strategies; assist the patient and family to acknowledge their fear; provide a safe environment to discuss fear; explore cultural influences that may enhance fear; utilize therapeutic touch as appropriate to decrease fear|
|Family process (Related to failure to maintain a viable pregnancy)||Stated feelings of failing to provide children; change in communication patterns between partners regarding having children; alterations in intimacy||Offer family counseling; facilitate opportunities for the patient and spouse to express their feelings and their perception of the problem; evaluate patient and family weaknesses, strengths, and coping strategies; help the family and patient break down concerns into manageable parts|
|Grief (Related to fetal loss; inability to carry child to term)||Apparent psychological and emotional distress; withdrawal; detachment; loss of appetite; refusal to participate in activities of daily living; anger; blame||Assess decision-making ability; encourage expression of grief; provide contact information for grief support group; assist to identify current support group; provide social services referral as appropriate; allow the patient and spouse to relieve the loss and express feelings|
- Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
- Patient Teaching: Inform the patient this test can assist in screening for pregnancy, identifying tumors, and evaluating fetal health.
- Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
- Obtain a history of the patient’s endocrine, immune, and reproductive systems; symptoms; and results of previously performed laboratory tests and diagnostic and surgical procedures.
- Record the date of the last menstrual period and determine the possibility of pregnancy in perimenopausal women.
- Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
- Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
- Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
- Note that there are no food, fluid, or medication restrictions unless by medical direction.
- Potential complications: N/A
- Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
- Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
- Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
- Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
- Promptly transport the specimen to the laboratory for processing and analysis.
- Inform the patient that a report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient.
- Social and Cultural Considerations: Recognize anxiety related to abnormal test results, and encourage the family to seek counseling if concerned with pregnancy termination or to seek genetic counseling if a chromosomal abnormality is determined. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Decisions regarding elective abortion should take place in the presence of both parents. Provide a nonjudgmental, nonthreatening atmosphere for discussing the risks and difficulties of delivering and raising a developmentally challenged infant, as well as exploring other options (termination of pregnancy or adoption). It is also important to discuss feelings the mother and father may experience (e.g., guilt, depression, anger) if fetal abnormalities are detected.
- Social and Cultural Considerations: Offer support, as appropriate, to patients who may be the victims of rape or sexual assault. Educate the patient regarding access to counseling services. Provide a nonjudgmental, nonthreatening atmosphere for a discussion during which risks of sexually transmitted diseases are explained. It is also important to discuss problems the victim of sexual assault may experience (e.g., guilt, depression, anger) if there is possibility of pregnancy related to the assault.
- Social and Cultural Considerations: In patients with carcinoma, recognize anxiety related to test results and offer support. Provide teaching and information regarding the clinical implications of abnormal test results, as appropriate. Educate the patient regarding access to counseling services, as appropriate.
- Depending on the results of this procedure, additional testing may be performed to evaluate or monitor the patient’s condition and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
- Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
- Instruct the patient in the use of home test kits for pregnancy approved by the U.S. Food and Drug Administration, as appropriate.
- Answer any questions or address any concerns voiced by the patient or family.
Expected Patient Outcomes
- States understanding that surgical intervention may be necessary in the event of fetal demise.
- States understanding that the purpose of surgical intervention post-miscarriage is to ensure all of the tissue is removed to prevent infection and facilitate future viable pregnancies.
- Accurately describes symptoms that may indicate a miscarriage and should be reported to the HCP.
- Accurately describes the purpose of future laboratory (HCG) studies to monitor and verify the continuation of the pregnancy.
- Agrees to attend a support group for those who have experienced fetal loss.
- Complies with scheduled follow-up laboratory studies to monitor pregnancy.
- Related tests include biopsy chorionic villus, Chlamydia group antibody, chromosome analysis, CMV, estradiol, fetal fibronectin, α1-fetoprotein, CBC, hematocrit, CBC hemoglobin, CBC WBC count and differential, progesterone, rubella antibody, rubeola antibody, syphilis serology, toxoplasma antibody, US abdomen, and US biophysical profile obstetric.
- Refer to the Endocrine, Immune, and Reproductive systems tables at the end of the book for related tests by body system.