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Test Code E2 Estradiol, Plasma or Serum, LAB523

Additional Codes






Immunoenzymatic Chemiluminescent Assay

Performing Laboratory

St. Luke's Hospital, Cedar Rapids

Specimen Requirements



Preferred: Gold-top serum

Acceptable:  Red-top serum, Green-top (heparin) tube, Lavender-top (EDTA) plasma

Specimen: 0.5 mL of serum or plasma



  • Room temperature:  20 hours.  Do not use samples that have been stored at room temperature for longer than 20 hours.
  • Refrigeration (2°-8°C):  48 hours
  • Frozen (≤ -20°C): 6 months.  Freeze samples only once and mix thoroughly after thawing. 


Transport Temperature: Refrigerated preferred, ambient for 20 hours acceptable

Reference Values



<40 pg/mL

Female non-pregnant value


  Follicular phase (-12 to -4 days)

20 – 144 pg/mL

  Midcycle (-3 to +2 days)

64 – 357 pg/mL

  Luteal Phase (+4 to +12 days)

56 – 214 pg/mL

Post-menopausal females (untreated)

<32 pg/mL


Day(s) Test Set Up

Tuesday and Friday

STAT testing available Monday through Friday, day shift only

Test Classification and CPT Coding


Useful For

Elevated estradiol levels in females may also result from primary or secondary ovarian hyperfunction.  Very high estradiol levels are found during the induction of ovulation1 for assisted reproduction therapy or in pregnancy. Decreased estradiol levels in females may result from either the lack of ovarian synthesis (primary ovarian hypofunction and menopause) or a lesion in the hypothalamus-pituitary axis (secondary ovarian hypofunction). Estradiol levels are normally low in males. Elevated estradiol levels in males may be due to increased aromatization of androgens, resulting in gynecomastia.