Labs
What your blood test results mean, such as cholesterol, blood sugar, and thyroid tests, and how to follow them over the years.
What each iron test measures, the WHO's ferritin thresholds for iron deficiency and overload, why inflammation raises ferritin, and why serum iron alone says little.
November 4, 2026 · 2 min read
Why TSH moves in the opposite direction to thyroid hormone, how TSH and free T4 together sort out over- and underactive thyroid, what TPO antibodies add, and what can throw the results off.
November 4, 2026 · 3 min read
What the red cell, white cell, and platelet results on a full blood count measure, the WHO's haemoglobin thresholds for anaemia, what red cell size says about the cause, and how the white cell differential breaks down.
November 4, 2026 · 3 min read
What each liver test measures, the pattern that points to liver cells or bile ducts, why a healthy ALT is lower than many labs print, and harmless reasons for a high result, such as a hard workout or Gilbert syndrome.
November 4, 2026 · 3 min read
What serum vitamin B12 and folate measure, why there's no sharp cut-off for deficiency, how homocysteine and methylmalonic acid help, who is at risk, and why lowering homocysteine hasn't prevented heart attacks.
November 4, 2026 · 3 min read
Why low HDL cholesterol marks higher heart risk but raising it with drugs hasn't helped, why very high HDL isn't protective, and how HDL enters the cholesterol ratio and non-HDL cholesterol.
November 4, 2026 · 3 min read
Vitals
What a CGM shows in people without diabetes, the diagnostic thresholds for fasting and two hours after glucose, why a spike after a meal isn't a diagnosis, and how to read your own curves.
November 4, 2026 · 3 min read
The usual cut-offs for triglycerides, fasting and not, what raises them, why very high levels are an emergency for the pancreas, and what lowering them does and doesn't do for the heart.
November 4, 2026 · 3 min read
How C-reactive protein measures inflammation, why the high-sensitivity test is used for heart risk, the AHA and CDC's under 1, 1 to 3, and over 3 mg/L bands, and why a single value can mislead.
November 4, 2026 · 2 min read
Why most testosterone is bound to proteins, when free testosterone matters, how to time the test, what a harmonized normal range for men looks like, and why one low result isn't a diagnosis.
November 4, 2026 · 4 min read
What prostate-specific antigen measures, why no PSA level proves or rules out cancer, what free PSA adds, what raises it temporarily, and what the US Preventive Services Task Force says about screening.
November 4, 2026 · 3 min read
What anti-Müllerian hormone measures, why it predicts response to IVF but not your chance of conceiving naturally, what a large study found, and how to read a result.
November 4, 2026 · 2 min read
How HbA1c reflects your average blood sugar over two to three months, the ADA's 5.7% and 6.5% thresholds, the conditions that make it read falsely high or low, and how it relates to fasting glucose.
November 4, 2026 · 2 min read
How apolipoprotein B counts the particles that cause atherosclerosis, why it can disagree with LDL cholesterol, what US and European guidelines say about it, and how non-HDL cholesterol compares.
November 4, 2026 · 2 min read
How estimated glomerular filtration rate is calculated from blood tests, the KDIGO stages of chronic kidney disease, why muscle mass skews creatinine, and why the combined equation is the most accurate.
November 4, 2026 · 3 min read
How the homeostatic model assessment turns fasting glucose and insulin into an estimate of insulin resistance, why there's no universal cut-off, and what limits it.
November 4, 2026 · 2 min read
Why Lp(a) is a mostly inherited risk factor for heart attack and stroke, why European guidance says to measure it once in every adult, the thresholds in mg/dL and nmol/L, and why the two units don't convert.
November 4, 2026 · 2 min read
How the omega-3 index measures EPA and DHA in your red blood cells, where its 4% and 8% marks come from, what trials of fish oil found, and how it relates to the omega-3s you eat.
November 4, 2026 · 4 min read
Why experts disagree on the level, the National Academies' 20 ng/mL (50 nmol/L), the Endocrine Society's 2024 advice against routine testing, what large trials found, and how much vitamin D the Dietary Reference Intakes recommend.
November 4, 2026 · 3 min read
The eight tests in a basic metabolic panel, what each says about your fluid balance, kidneys, and blood sugar, what a comprehensive panel adds, and how to read results against your lab's range.
November 4, 2026 · 4 min read
How labs calculate LDL cholesterol with the Friedewald, Martin-Hopkins, and NIH equations, why they disagree when triglycerides are high or LDL is low, and when a direct measurement is used.
November 4, 2026 · 3 min read
Where the "normal" range beside each blood test result comes from, why healthy people fall outside it, and how to read your results over the years.
October 23, 2026 · 5 min read