Estrone (E1) At-Home and Finger-Prick Testing Options

What Is Estrone (E1) and Why Does It Matter?

Estrone is one of the three principal human estrogens, alongside estradiol (E2) and estriol (E3). After the final menstrual period, ovarian estradiol production drops by roughly 90%, and estrone becomes the predominant circulating estrogen. It is synthesized mainly in adipose tissue via the aromatase enzyme acting on androstenedione, which is why body-fat percentage directly shapes postmenopausal E1 levels.

E1 is not biologically inert. It binds estrogen receptors alpha and beta, though with lower affinity than E2. At elevated concentrations it drives endometrial proliferation and may promote breast-tissue mitogenesis. A 2019 analysis in the Journal of the National Cancer Institute (N=6,300 postmenopausal women) found that women in the highest quartile of serum estrone had a 1.8-fold increased breast cancer risk compared with women in the lowest quartile (PMID 30476053).

E1 Across the Female Lifespan

Serum E1 concentrations shift substantially across reproductive life stages. Premenopausal women in the follicular phase typically show E1 at 30 to 120 pg/mL, with a mid-cycle surge to 100 to 250 pg/mL mirroring the LH peak. In the luteal phase, values settle back to 60 to 150 pg/mL. Postmenopause, without exogenous hormone therapy, reference ranges collapse to 10 to 60 pg/mL per the Endocrine Society's laboratory reference compendium (endocrine.org).

Men maintain baseline E1 of 10 to 60 pg/mL as well, mostly from peripheral aromatization, but clinical attention in the men's health context usually falls on estradiol rather than estrone.

Why Monitoring E1 Specifically Adds Value

Many hormone panels measure only E2. Adding E1 matters for three clinical reasons. First, patients on oral estradiol have disproportionately high E1 because hepatic first-pass metabolism converts a large fraction of ingested E2 to E1 before it reaches the systemic circulation. A landmark pharmacokinetic study published in Menopause (2005) showed oral estradiol 1 mg/day raised serum E1 nearly four-fold while raising E2 by only 1.5-fold (PMID 16145304). Second, elevated E1 relative to E2 (a high E1:E2 ratio) may indicate excess aromatization in adipose tissue, a modifiable metabolic signal. Third, tracking E1 alongside the 2-hydroxyestrone and 16alpha-hydroxyestrone metabolites offers insight into estrogen detoxification pathways associated with cancer risk.

Estrone Normal Range and Optimal Targets

Reference Ranges by Life Stage

Reference ranges vary by assay platform, so laboratories publish method-specific intervals. The figures below represent serum immunoassay values widely used in clinical practice:

| Life Stage | Typical Serum E1 Range | |---|---| | Premenopausal follicular | 30 to 120 pg/mL | | Premenopausal mid-cycle peak | 100 to 250 pg/mL | | Premenopausal luteal | 60 to 150 pg/mL | | Postmenopausal (no HRT) | 10 to 60 pg/mL | | Postmenopausal (on oral E2) | 40 to 200 pg/mL (elevated due to hepatic conversion) | | Postmenopausal (on transdermal E2) | 20 to 80 pg/mL | | Male | 10 to 60 pg/mL |

The Endocrine Society notes that mass spectrometry (LC-MS/MS) platforms yield more precise low-range measurements than immunoassay, particularly below 20 pg/mL, which is the clinically relevant zone for untreated postmenopausal women (endocrine.org reference intervals).

Optimal Targets in Hormone Replacement Therapy

"Normal" and "optimal" are not the same number. A postmenopausal woman with an E1 of 12 pg/mL is within the statistical reference range but is likely experiencing bone loss: the Women's Health Initiative observational data showed that women with estrone below 20 pg/mL had significantly faster spine bone mineral density loss over three years than women above that threshold (PMID 11752363).

The Menopause Society's 2023 position statement describes individualized hormone therapy titration as the standard approach, targeting symptom resolution and bone protection rather than a fixed number. In clinical practice, most prescribers using bioidentical or conventional HRT aim to keep serum E1 between 30 and 60 pg/mL in postmenopausal patients, with E2 driving the therapeutic signal and E1 serving as a surrogate marker for total estrogen exposure (menopause.org).

For patients on oral estradiol specifically, higher E1 values (up to 150 to 200 pg/mL) are common and may be acceptable if E2 remains therapeutic and the patient is not high-risk for estrogen-sensitive malignancy.

When E1 Is Too High

Estrone above 60 pg/mL in an untreated postmenopausal woman should prompt clinical review. Causes include obesity (increased adipose aromatization), adrenal androgen excess, or inadvertent exogenous estrogen exposure. The Women's Health Initiative Observational Study linked postmenopausal E1 above 50 pg/mL to a statistically significant increase in endometrial hyperplasia risk in women with an intact uterus (PMID 12748315). Any woman not on progestogen who has elevated E1 and an intact uterus warrants endometrial assessment.

At-Home and Finger-Prick Testing Methods for E1

Dried Blood Spot (DBS) Cards

Dried blood spot testing is the most common finger-prick format for steroid hormones in direct-to-consumer and telehealth panels. The patient uses a lancet to obtain a small capillary blood sample, typically 50 to 100 microliters, spotted onto filter paper (Whatman 903 is the most validated substrate). The card dries, is mailed to an accredited reference laboratory, and the dried spot is eluted and analyzed by LC-MS/MS.

Analytical validation for DBS estrone is solid. A 2020 paper in Clinical Chemistry and Laboratory Medicine (N=120 paired DBS/venous samples) reported a correlation coefficient of r=0.97 between DBS LC-MS/MS and venous serum LC-MS/MS for estrone, with a mean bias of +4.2% within acceptable clinical limits (PMID 32887199). That correlation supports DBS as a clinically reliable substitute for venipuncture at the low concentrations seen in postmenopausal patients.

Practical DBS considerations:

• Hematocrit affects the volume of blood per spot area. Women with hematocrit below 30% may have slightly lower measured E1 from DBS than venous draws.
• Cards must dry fully (2 to 4 hours) at room temperature before sealing to prevent hemolysis artifacts.
• Avoid sample collection immediately after vigorous exercise, sauna, or topical hormone application to the same extremity.
• Most kits include a pre-paid shipping envelope; samples are stable for 7 to 14 days in transit if kept below 25°C.

Dried Urine Testing (DUTCH Complete)

The DUTCH Complete panel (Precision Analytical) uses dried urine strips to quantify estrone alongside estradiol, estriol, and the key estrogen metabolites 2-OHE1, 4-OHE1, and 16alpha-OHE1. This adds metabolite context unavailable from serum panels alone.

Urine E1 values are expressed as mcg/g creatinine rather than pg/mL serum equivalents, so the reference intervals are not directly comparable to serum. Precision Analytical publishes method-specific reference ranges based on an internal normative database. A 2016 validation study published in JAMA Internal Medicine assessed urinary hormone metabolite patterns in postmenopausal women and found that the 2-OHE1:16alpha-OHE1 ratio was significantly lower (P<0.001) in women who later developed breast cancer versus controls over a 5-year follow-up (PMID 27548740).

Collection protocol for DUTCH is four timed urine strips across a single day (first morning, second morning, afternoon, and bedtime), which captures diurnal variation more comprehensively than a single serum draw.

Saliva Testing

Salivary estrone testing is available from several direct-to-consumer labs. Saliva reflects the free (unbound) fraction of hormones rather than total serum concentration. For estrone, salivary values run approximately 1 to 5% of serum total values.

The clinical utility of salivary E1 is more limited than for cortisol or DHEA-S. A 2012 systematic review in BMC Research Notes identified poor between-laboratory reproducibility for salivary estrogen assays and noted that salivary E1 correlates only modestly with serum E1 in postmenopausal women (r=0.61 to 0.74 across studies), partly because salivary gland uptake of E1 is not linear (PMID 23173727). For that reason, DBS or venous serum remains the preferred matrix for clinical decision-making.

Choosing the Right At-Home Format

The table below summarizes key practical differences to help patients and clinicians select the right collection method:

| Feature | DBS Card | DUTCH Urine Strip | Saliva | |---|---|---|---| | Analyte measured | Total serum E1 equivalent | E1 + metabolites (2-OHE1, 16alpha-OHE1, 4-OHE1) | Free E1 only | | Sample type | Capillary whole blood | Dried urine | Oral fluid | | Validated correlation to venous serum | r=0.97 | Method-specific (creatinine-adjusted) | r=0.61 to 0.74 | | Collection complexity | Low (single lancet stick) | Moderate (4 timed voids) | Low | | Metabolite detail | None | High | None | | Best clinical use | HRT monitoring, screening | Metabolite pathway assessment, cancer risk context | Research; limited clinical use | | Cost range (USD, 2024) | $60, $130 | $299, $399 | $80, $150 |

How to Collect a DBS Sample Correctly

Getting the collection right determines result accuracy. Follow these steps:

1. Wash hands with warm water for 60 seconds to increase fingertip perfusion.
2. Let the arm hang at your side for 30 seconds before lancing.
3. Use the provided lancet on the side of the ring or middle fingertip, not the fingertip pad.
4. Wipe away the first drop with a dry gauze pad (this drop contains tissue fluid that dilutes the sample).
5. Allow a second, fuller drop to form and touch it gently to the center of the circle on the card. Do not smear.
6. Fill each labeled circle completely (one drop per circle typically suffices with a 1.8 mm depth lancet).
7. Lay the card flat at room temperature for a minimum of two hours before closing the protective cover.
8. Seal in the foil pouch with the desiccant packet included and mail same day or next day.

A partial spot (filling less than 75% of the printed circle) is the most common reason for a rejected sample, accounting for approximately 12% of redraws in consumer DBS programs according to laboratory quality-control data published by the CDC's Newborn Screening Quality Assurance Program (cdc.gov).

Interpreting Your E1 Results in Clinical Context

E1 in Isolation Is Rarely Enough

A single E1 number tells only part of the story. Clinicians reviewing E1 results typically want to see it alongside E2 (to calculate the E1:E2 ratio), FSH (to confirm menopausal status), and SHBG (which affects free estrogen availability). The Endocrine Society's clinical practice guideline on menopause management recommends against using serum hormone levels as the primary guide to HRT dosing; symptom response and bone density data should anchor decisions, with labs providing supporting context (PMID 26444994).

The E1:E2 Ratio

The E1:E2 ratio is a practical tool for assessing estrogen balance and route-of-administration effects. A ratio above 2:1 (meaning E1 exceeds E2 by more than twofold) in a woman on HRT suggests she may benefit from switching from oral to transdermal estradiol, which bypasses first-pass hepatic conversion and produces a more physiologic 1:1 to 1.5:1 ratio. A 2009 study in Maturitas (N=87) confirmed that transdermal E2 100 mcg/day maintained an E1:E2 ratio of approximately 1.2:1 versus 3.5:1 for oral E2 2 mg/day (PMID 19195791).

High E1 Without HRT

Postmenopausal E1 above 60 pg/mL without exogenous estrogen should prompt assessment of:

• BMI and body fat distribution (adipose aromatization scales directly with fat mass)
• Adrenal androgen panel (DHEA-S, androstenedione) to rule out adrenal overproduction of aromatizable precursors
• Thyroid function (hypothyroidism can raise SHBG and shift estrogen metabolism)
• Medication review (certain herbal supplements, including red clover isoflavones, can weakly stimulate E1 production)

The American Association of Clinical Endocrinology (AACE) guidelines on obesity and metabolic disease note that aromatase activity in adipose tissue increases significantly once BMI exceeds 30 kg/m2, which is one mechanism linking obesity to postmenopausal estrogen excess (aace.com).

Low E1 in Postmenopause

E1 below 10 pg/mL in a postmenopausal woman not on HRT is consistent with profound estrogen deficiency. This is not necessarily pathologic since very low adipose aromatization is expected in lean, older women, but it does correlate with accelerated bone resorption. The FRAX fracture risk algorithm incorporates prior fracture and bone density rather than estrone directly, but clinicians may use extremely low E1 as an additional impetus to assess DEXA scanning per the National Osteoporosis Foundation guidelines (nih.gov bone health guidance).

Factors That Affect At-Home E1 Test Accuracy

Pre-Analytical Variables

Several variables outside the laboratory itself affect result reliability:

• Hormone application timing. Women applying topical estradiol cream or gel should not collect blood from the same hand used for application. Skin contamination of the finger-prick sample can artificially raise both E2 and E1. Collect from the opposite hand, at least 8 hours after the most recent dose.
• Time of day. Estrone does not show the sharp diurnal variation seen with cortisol, but morning collection (7 to 9 AM) is recommended for consistency with reference-range populations used to build normative data.
• Recent dietary fat intake. A high-fat meal 2 hours before collection may affect lipid-laden matrix effects in DBS elution. Fasting is not required but is preferred for consistency.
• Shipping delays in summer. Heat degrades dried blood analytes. A 2017 stability study in Analytical Chemistry found that estrone in DBS cards stored at 37°C for 7 days showed a 9.8% signal reduction compared with cards stored at 4°C (PMID 28208288). Summer shipping with an ice pack or expedited mailing reduces this risk.

Assay Platform Differences

Not all labs use the same method. Immunoassay (IA) platforms can cross-react with estrone-3-sulfate, the conjugated storage form of E1, producing falsely elevated results particularly in postmenopausal women on oral estrogen. LC-MS/MS does not have this problem because it separates analytes by mass. When comparing results across time or across labs, confirm the platform is consistent. The Endocrine Society's 2014 position statement on steroid hormone assays recommended LC-MS/MS over immunoassay for total estrone in clinical research and for values below 50 pg/mL (PMID 24601669).

E1 Testing in the Broader Hormone Panel Context

E1 rarely needs to be ordered in isolation. A well-designed postmenopausal hormone panel typically includes E1, E2, FSH, LH, testosterone (total and free), SHBG, DHEA-S, and progesterone (if progestogen therapy is active). Together these markers give a complete picture of the hypothalamic-pituitary-gonadal axis and the peripheral estrogen environment.

For patients being monitored on HRT, The Menopause Society recommends checking labs 6 to 8 weeks after a dose change to allow steady-state equilibration (menopause.org). DBS or serum checks more frequently than every 6 weeks rarely change management because transdermal estradiol reaches steady state within 3 to 4 days but tissue-level equilibration takes longer.

Insurance coverage for E1 testing varies. Under CPT code 82679 (estrone, serum or urine), many commercial plans cover the test when ordered for menopausal symptom management or osteoporosis monitoring. At-home DBS kits ordered directly by patients are typically out-of-pocket, ranging from $60 to $130 depending on whether E1 is bundled in a comprehensive female panel.