Blood Spot Thyroids + Dried Urine GCMS Estrogen Hormone Metabolites and LCMS Diurnal Hormones I

Thyroid-stimulating hormone is a glycoprotein secreted by anterior pituitary thyrotropes under hypothalamic thyrotropin-releasing hormone control. It binds thyroid follicular cell receptors and stimulates synthesis and release of thyroxine and triiodothyronine. Negative feedback from circulating thyroid hormones suppresses TSH, making it the most sensitive single marker of primary thyroid dysfunction.

TSH is the first-line test for thyroid evaluation. Elevations indicate primary hypothyroidism; suppression suggests hyperthyroidism or excessive thyroid hormone replacement. The dried blood spot platform enables home collection, though concordance with serum TSH should be confirmed for individual cases when clinical decisions hinge on borderline values.

Free T4 represents the unbound, biologically active fraction of thyroxine, the major secretory product of the thyroid gland. Thyroxine is deiodinated peripherally to the more potent triiodothyronine. Free T4 is less influenced by binding protein variation than total T4.

Free T4 confirms the direction and severity of thyroid dysfunction flagged by TSH. Low free T4 with elevated TSH defines overt primary hypothyroidism; high free T4 with suppressed TSH defines hyperthyroidism. Free T4 is also used to monitor levothyroxine dosing.

Free T3 is the unbound fraction of triiodothyronine, the most metabolically active thyroid hormone. Roughly 80 per cent of circulating T3 is generated by peripheral 5'-deiodination of T4 in liver and kidney, while the thyroid directly secretes the remainder.

Free T3 is useful when TSH and free T4 discordance occurs, when evaluating T3 toxicosis, and in functional assessments of thyroid hormone adequacy. Some patients with treated hypothyroidism report persistent symptoms despite normal TSH and free T4 but have low-normal or low free T3, prompting consideration of combination therapy.

TPO antibodies target thyroid peroxidase, the enzyme catalysing iodine organification and thyroglobulin iodination. Their presence marks autoimmune thyroid disease, most commonly Hashimoto thyroiditis. Antibody titre does not strictly correlate with disease activity but persistence indicates ongoing autoimmunity.

Positive TPO antibodies confirm autoimmune aetiology in hypothyroidism and predict progression of subclinical hypothyroidism to overt disease. They are also associated with miscarriage risk in pregnancy and are a component of thyroid autoimmunity screening before assisted reproduction.

Estrone is the predominant circulating oestrogen after menopause, produced by peripheral aromatisation of androstenedione in adipose tissue. In premenopausal women it interconverts with oestradiol via 17β-hydroxysteroid dehydrogenase. Urinary E1 reflects tissue exposure integrated over the collection window.

Dried-urine oestrogen metabolite testing aims to assess oestrogen production and metabolism pathways, with functional practitioners using the pattern to infer hormonal balance and metabolic risk. It is not a replacement for serum oestradiol in standard endocrine diagnosis.

Oestradiol is the most potent naturally occurring oestrogen, secreted by ovarian granulosa cells in premenopausal women and in smaller amounts by the adrenal cortex and peripheral tissues. Urinary oestradiol measurement captures unconjugated and conjugated forms excreted over the collection period.

Urinary E2 is used in functional hormone assessment to evaluate ovarian function, menopausal transition, and exogenous hormone replacement. Standard diagnosis of hypogonadism and ovarian failure relies on serum oestradiol; urine metabolites provide an adjunct picture.

Estriol is a weaker oestrogen, formed by 16α-hydroxylation of oestrone and oestradiol. In non-pregnant women it is a minor metabolite; during pregnancy the fetoplacental unit produces large amounts. Urinary E3 reflects hepatic and gut metabolism of parent oestrogens.

In functional hormone assessment E3 is viewed as a marker of oestrogen metabolism. Estriol has historically been used as a pregnancy marker but has no routine diagnostic role in non-pregnant adults outside functional medicine.

2-Hydroxyestrone is the principal C2-hydroxylated oestrogen metabolite, formed by cytochrome P450 1A enzymes. It has weak oestrogenic activity and is further conjugated and excreted. The C2 pathway is considered the 'protective' route in functional models.

Functional practitioners interpret urinary 2-OHE1 as part of an oestrogen metabolism profile, with higher 2-hydroxylation theoretically favouring lower proliferative risk. This framework is not adopted in mainstream endocrinology, and there are no validated clinical thresholds.

4-Hydroxyestrone is a minor C4-hydroxylated metabolite formed by CYP1B1. It can undergo redox cycling to form quinones, which may cause oxidative DNA damage. Animal and in-vitro data have linked 4-hydroxylated catechols to carcinogenesis, but clinical validation is limited.

Functional practitioners view elevated urinary 4-OHE1 as a marker of 'unfavourable' oestrogen metabolism, though evidence that the measurement predicts disease is contested. It is not used in standard oncology or endocrine risk stratification.

16α-Hydroxyestrone is formed by CYP3A-mediated 16α-hydroxylation of oestrone. It retains significant oestrogenic activity and cannot be further hydroxylated, so it remains active longer than 2-hydroxylated metabolites.

Functional hormone models propose that a high 2-OHE1:16α-OHE1 ratio is protective, while a low ratio may signal increased proliferative stimulus. Epidemiological data are mixed, and the ratio is not part of consensus breast cancer or endocrine risk assessment.

2-Methoxyestrone is formed by catechol-O-methyltransferase methylation of 2-hydroxyestrone, effectively inactivating it and preparing it for conjugation and excretion. Methylation adequacy depends on COMT activity and S-adenosylmethionine availability.

Functional practitioners interpret the 2-OHE1:2-MeOE1 ratio as an index of phase II methylation capacity. Low methylation is theorised to allow catechol accumulation and redox cycling, though clinical thresholds and outcomes are not validated.

4-Methoxyestrone is the methylated conjugate of 4-hydroxyestrone, produced by COMT. Methylation prevents quinone formation and is considered protective against oxidative DNA damage in functional models.

Functional practitioners view the 4-OHE1:4-MeOE1 ratio as a marker of methylation efficiency and oxidative risk. There is no consensus validation or clinical threshold for this measurement.

2-Hydroxyestradiol is the C2-hydroxylated metabolite of oestradiol, formed by the same CYP1A pathway as 2-hydroxyestrone. It is rapidly methylated and conjugated.

In functional oestrogen metabolism profiles 2-OHE2 is grouped with 2-OHE1 as a 'protective' metabolite. There is no established clinical use for this measurement outside functional practice.

Cortisol is the principal glucocorticoid secreted by the adrenal zona fasciculata under ACTH control. It follows a diurnal rhythm, peaking shortly after waking and declining through the day. Urinary free cortisol integrates secretion over the collection window and is not influenced by binding proteins.

Diurnal urinary cortisol mapping is used in functional adrenal assessment to identify flattened or dysregulated rhythms. Standard diagnosis of Cushing syndrome and adrenal insufficiency relies on serum cortisol, dexamethasone suppression, and 24-hour urinary free cortisol; dried-urine fractionated cortisol is an adjunct functional tool.

Cortisone is the inactive 11-keto metabolite of cortisol, formed by 11β-hydroxysteroid dehydrogenase type 2. Tissue-specific interconversion between cortisol and cortisone regulates local glucocorticoid activity. Urinary cortisone reflects both direct adrenal secretion and peripheral metabolism.

The cortisol:cortisone ratio in urine is used in functional models to infer 11β-HSD activity and tissue glucocorticoid exposure. It is not part of standard endocrine evaluation.

Progesterone is synthesised by the corpus luteum after ovulation and by the placenta during pregnancy. In men and postmenopausal women it is an intermediate in adrenal steroidogenesis. Urinary progesterone reflects integrated secretion; it is not routinely used for ovulation confirmation, which relies on serum measurement.

Dried-urine progesterone is used in functional hormone panels to assess luteal adequacy and oestrogen:progesterone balance. Standard diagnosis of luteal-phase defects and anovulation uses mid-luteal serum progesterone.

Testosterone is the principal androgen, secreted by testicular Leydig cells in men and by the ovary and adrenal in women. Urinary testosterone captures unconjugated and conjugated fractions excreted over the collection period.

Urinary testosterone is used in functional hormone profiles to assess androgen status. Standard diagnosis of hypogonadism and androgen excess relies on early-morning serum total and free testosterone; urine metabolites provide an adjunct picture.

DHEA is secreted by the adrenal zona reticularis and serves as a precursor to androgens and oestrogens. Serum DHEA-S is the standard measure of adrenal androgen reserve; urinary DHEA is less commonly used clinically.

Dried-urine DHEA is included in functional adrenal and hormone panels to assess adrenal androgen output and infer 'adrenal reserve'. Standard evaluation of adrenal insufficiency uses serum cortisol and ACTH stimulation.