Biomarker library

A plain-English explanation of every blood test marker we measure, with UK reference ranges, symptoms of high and low, and which WMG Health panel includes it. Reviewed by our clinical team and updated when guidance changes.

36 markers
9 categories
UK reference ranges
06/02 last reviewed
Fe Iron Vit Vitamins Thy Thyroid And Androgens Oes Oestrogens Adr Adrenal Met Metabolic Inf Inflammation Imm Immunity

Read markers together

Marker pair interpretation guides

Some markers are misleading when read alone. Ferritin can hide deficiency in inflammation; TSH alone misses central hypothyroidism; total testosterone alone misses SHBG-driven cases. These guides explain how to read the highest-value pairs together with 4-quadrant interpretation tables.

Iron studies pair

Ferritin and TIBC (total iron binding capacity)

Ferritin and TIBC are interpreted together because ferritin can be misleadingly normal or even raised during inflammation, while TIBC moves in the opposite direction during true iron deficiency.

Read guide →

Thyroid first-line pair

TSH and Free T4

TSH and free T4 are the first-line thyroid axis pair: TSH reflects the pituitary signal and free T4 reflects what the thyroid actually delivers. Together they distinguish primary thyroid disease from secondary pituitary disease.

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Calculated free testosterone pair

Total testosterone and SHBG (sex hormone binding globulin)

Total testosterone alone can be misleading because most of it is bound to SHBG and biologically inactive. The pair allows calculated free testosterone (the Vermeulen formula), which is what BSSM 2017 UK guidelines actually use for testosterone deficiency diagnosis.

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Methylation B-vitamin pair

Vitamin B12 and Folate

B12 and folate are interpreted together because they share the methylation pathway, present with similar symptoms (macrocytic anaemia, fatigue, glossitis), and supplementing one without the other can mask the deficiency of the other.

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Diabetes diagnosis pair

HbA1c and Fasting glucose

HbA1c and fasting glucose are interpreted together because they capture different time windows: HbA1c reflects average glucose over 8-12 weeks, while fasting glucose is a single-moment reading. They agree in most patients but disagree usefully in patients with rapid glucose changes, haemoglobinopathies, or recent illness.

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All marker pair guides →

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Our menu covers more markers than the standard panels. Build a custom panel with whatever combination you and your clinician think is most useful.

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