lab-guides
How to read your biomarkers: HbA1c, TSH, lipid panel, vitamin D, ApoB and more — what each marker means, optimal ranges by age, every claim sourced.
BUN — Protein Waste and Kidney Clearance
Blood urea nitrogen tracks protein waste the kidneys clear — but dehydration and diet move it too, so it is never read alone.
Bilirubin — The Red-Cell Waste Product Your Liver Clears
Bilirubin is the waste product left when red blood cells break down. The direct/indirect split — not the total alone — is what determines the follow-up.
Serum Calcium — Bone, Parathyroid and Kidney in One Value
A calcium blood test measures the calcium circulating in your blood — not the calcium in your bones, which is why an out-of-range result is followed up rather than corrected with a supplement.
ALP — Liver and Bone in One Number
Alkaline phosphatase is concentrated in the liver, the bile ducts and the bones — which is exactly what makes a raised value ambiguous until you know which of the three it came from.
PSA — What the Test Does and Does Not Settle
PSA screens for prostate cancer but cannot show what is causing an abnormal level. Screening and the treatment it can lead to may cause more harm than benefit for many men — a shared decision, not a box to tick.
Albumin — The Protein That Carries Everything Else
Albumin is the most abundant protein in blood: it holds fluid inside the vessels and transports hormones, minerals and drugs — and it changes how other results on the same panel should be read.
Electrolytes — Sodium, Potassium, Chloride, Bicarbonate
The electrolyte panel measures the four minerals that govern fluid balance, nerve conduction and acid-base status: sodium, potassium, chloride and bicarbonate.
Iron Studies — Serum Iron, TIBC and Transferrin Saturation
Iron studies are a group, not a single test: serum iron, TIBC and transferrin saturation together separate iron deficiency from iron overload in a way that no single marker can.
CMP — The 14 Numbers on Your Annual Panel
The comprehensive metabolic panel is fourteen measurements from one blood draw: glucose, electrolytes, kidney markers, liver enzymes and proteins.
CBC — What the Full Blood Count Shows
The complete blood count measures red cells, white cells and platelets — the most commonly ordered blood test most people have never learned to read past the one number their doctor circled.
Urine ACR — Early Kidney Marker
The urine albumin-to-creatinine ratio detects kidney protein leak years before eGFR drops — the earliest available marker of diabetic and hypertensive kidney injury, from a single spot urine sample.
Progesterone — Luteal-Phase Confirmation
Progesterone rises after ovulation. A mid-luteal draw above 10 ng/mL confirms it happened; below that points to anovulation or a luteal-phase defect. The cycle day of the draw decides whether the number means anything.