Estriol, Serum
| Estriol, Serum | | | |
| Number | | 004614 |
| CPT | | 82677 |
| Synonyms | | E3, Serum ; Pregnancy, Estriol ; Unconjugated Estriol |
| Special Instructions | | State weeks of gestation on the request form. Usually done as serial measurement. |
| Specimen | | Serum |
| Volume | | 1 mL |
| Minimum Volume | | 0.3 mL (Note: This volume does not allow for repeat testing.) |
| Container | | Red-top tube or gel-barrier tube |
| Collection | | If a red-top tube is used, transfer separated serum to a plastic transport tube. All specimens should be drawn at the same time of day to allow comparison of values. |
| Storage Instructions | | Refrigerate |
| Patient Preparation | | Patient usually in third trimester of pregnancy |
| Causes for Rejection | | Plasma specimen |
| Reference Interval | | See table.
| Gestational Week | Median
(ng/mL) | Central 95% Range
(ng/mL) | | 27 | 6.5 | 2.9-12.7 | | 28 | 7.3 | 3.3-14.3 | | 29 | 8.2 | 3.7-16.0 | | 30 | 9.2 | 4.1-17.9 | | 31 | 10.3 | 4.6-19.9 | | 32 | 11.4 | 5.1-22.1 | | 33 | 12.7 | 5.7-24.4 | | 34 | 14.0 | 6.3-27.0 | | 35 | 15.5 | 7.0-29.7 | | 36 | 17.0 | 7.7 to >30 | | 37 | 18.7 | 8.5 to >30 | | 38 | 20.4 | 9.3 to >30 | | 39 | 22.3 | 10.2 to >30 | | 40 | 24.3 | 11.1 to >30 |
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| Use | | Evaluate fetal distress and placental function in the management of patients facing complications such as pre-eclampsia, fetal growth retardation, diabetes, Rh immunization, choriocarcinoma, and hydatidiform mole. May be elevated in hydrops fetalis in the presence of a dying fetus. May be low in the presence of a living anencephalic fetus. |
| Limitations | | Single values are almost impossible to interpret; trends in a series of measurements are much more important. May be low in case of placental sulfatase deficiency in the presence of a healthy baby. Other causes of decreased estriol levels include subjects living at high altitudes, anemia, severe liver disease, and a variety of drugs.1 Estriol may be increased with multiple pregnancy2 and with oxytocin.2 It is not reliable in the presence of renal disease.1,2 |
| Methodology | | Immunochemiluminometric assay (ICMA) |
| Additional Information | | Estriol, E3, is synthesized in the placenta from 16-α-hydroxydehydroepiandrosterone of fetal origin. Thus, normal production can serve as a measure of the integrity of the fetoplacental unit. Sequential monitoring of estriol in high risk pregnancy has made possible early intervention and fetal salvage. Chronically low estriol values are found in intrauterine growth retardation but also are sometimes seen in normal pregnancy. A decreasing trend is indicative of fetal distress. The sensitivity and specificity of this test for detecting fetal distress are very poor; thus its use for this purpose has been largely abandoned. Combined evaluation of unconjugated serum estriol, maternal serum hCG, maternal serum AFP, and maternal age has value in predicting risk for fetal chromosomal abnormalities during pregnancy. The use of maternal serum AFP, hCG, and estriol predicts 65% of Down syndrome, as opposed to 28% if only serum AFP is used.3,4,5 |
| Footnotes | | - Catanzarite VA, Perkins RP, and Pernoll ML, “Assessment of Fetal Well-Being,” Current Obstetric & Gynecologic Diagnosis & Treatment 1987, Pernoll ML and Benson RC, eds, Norwalk, CT: Appleton & Lange, 1987, 279-302.
- Speroff L, Glass RH, and Kase NG, Clinical Gynecologic Endocrinology and Infertility, 4th ed, Baltimore, MD: Williams & Wilkins, 1989.
- White RS 3rd, “Down Syndrome: Current Screening Technique,” South Med J, 1989, 82(12):1483-6.
- Heyl PS, Miller W, and Canick JA, “Maternal Serum Screening for Aneuploid Pregnancy by Alpha-Fetoprotein, hCG, and Unconjugated Estriol,” Obstet Gynecol, 1990, 76(6):1025-31.
- MacDonald ML, Wagner RM, and Slotnick RN, “Sensitivity and Specificity of Screening for Down Syndrome With Alpha-Fetoprotein, hCG, Unconjugated Estriol, and Maternal Age,” Obstet Gynecol, 1991, 77(1):63-8
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| References | | Bashore RA and Westlake JR, “Plasma Unconjugated Estriol Values in High-Risk Pregnancy,” Am J Obstet Gynecol, 1977, 128(4):371-80. Bennett DB and Wells DJ, “Endocrinology,” Clinical Chemistry: Principles, Procedures, Correlations, Bishop ML, Duben-VonLaufen JL and Fody EP, eds, Philadelphia, PA: JB Lippincott Co, 1985, 307-43. |
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