Estriol, Free, Unconjugated (E3)
Test Code: 4009CPT: 82677
|Use||Estriol (E3) is one of the three major naturally occurring estrogens, the others being estradiol (E2) and estrone (E1). In non-pregnant females, the major estrogen is estradiol produced by the ovaries. During pregnancy, estriol is secreted by the placenta and fetus and becomes the dominant estrogen form.¹ Estriol production is very low in men and non-pregnant women in comparison to levels produced during pregnancy. The primary form of estriol measured during pregnancy is unconjugated estriol (also referred to as “free” estriol or uE3).|
|Clinical Utility||Maternal serum uE3 levels have been used as a functional marker of the fetal-placental unit and in the evaluation of pregnancy complications.² Generally, a healthy fetal-placental unit will generate increasing amounts of estriol throughout pregnancy, resulting in a corresponding increase in maternal serum uE3.|
|Intended Patient Population||18+ and Older Adult Males & Females|
|Patient Preparation||None Specified|
|Volume||4mL Whole Blood (1mL Serum/Plasma)|
|Min Sample Volume||0.6 mLs|
|Reference Ranges||M ≥ 18 yrs old; <0.16 ng/mL
F Non-Pregnant ≥ 18 yrs old; <0.08 ng/mL
|Analytical Measurement Range||N/A|
|Test Methodology||Chemiluminescent Immunoassay|
|Test Turnaround Time||7 Days|
|Limitations||Potential interferences in the patient sample could be present and may cause erroneous results in immunoassays. Some examples that have been documented in literature include rheumatoid factor, endogenous alkaline phosphatase, fibrin, and proteins capable of binding to alkaline phosphatase.3,4 Carefully evaluate the results of patients suspected of having these types of interferences.|
|Specimen Stability||7 Days RF|
|Laboratory Developed Test (LDT)||Yes|
|References||1. Haymond S, Gronowski A. Reproductive related disorders. In: Burtis CA, Ashwood ER, Bruns DE, editors. Tietz textbook of clinical chemistry and molecular diagnostics. 4th ed, St. Louis, Elsevier Saunders; 2006. Chapter 53, p. 2106.
2. Ashwood E, Knight GJ. Clinical chemistry of pregnancy. In: Burtis CA, Ashwood ER, Bruns DE, editors. Tietz textbook of clinical chemistry and molecular diagnostics. 4th ed, St. Louis, Elsevier Saunders; 2006. Chapter 54, p. 2155.
3. Lum G, Solarz D, Farney L. False Positive Cardiac Troponin Results in Patients Without Acute Myocardial Infarction. Labmedicine 2006; 37(9): 546-550.
4. Lingwood D, Ballantyne JS. Alkaline phosphatase-immunoglobulin conjugate binds to lipids in vitro, independent
of antibody selectivity. Journal of Immunological Methods 2006; 311: 174-177.