biomarker guides
170 articles in this field-note collection.
24-hour urine protein: collection, normal range, results
A 24-hour urine protein test adds up the protein you lose in a day. How to collect it, what's normal, the nephrotic range, and what it means in pregnancy.
ACTH blood test: normal range, high and low causes
ACTH is the pituitary signal that tells your adrenals to make cortisol. Here's a normal morning level, what high and low results mean, and when it's urgent.
Aldosterone test: normal levels, renin ratio and causes
Aldosterone controls salt and potassium. See normal levels, how to read it with renin, what a high ratio means, and who should be screened.
Ammonia blood test: normal range, high causes, next steps
Ammonia is a waste product your liver turns into urea. Here's the normal range, what raises it, how to read it with other tests, and when it's urgent.
Anti-CCP test: what a positive result means for RA
Anti-CCP is the most specific blood test for rheumatoid arthritis. What's normal, what a positive means, why the level matters, and when to get care.
Anti-Xa test: target levels for heparin, apixaban and more
Anti-Xa measures how much heparin or an Xa-blocking pill is working in your blood. The targets by drug, why draw timing matters, and when to act.
ANA test: positive results, titers and patterns explained
A positive ANA is common in healthy people. Here's what your titer and pattern mean, which follow-up antibodies matter, and when a result needs prompt care.
Band neutrophils (bands): what a high count means
Bands are young neutrophils. Here's what a normal band count is, what a left shift means, why labs disagree on bands, and when high bands are urgent.
Base excess blood test: normal range, low and high causes
Base excess shows the metabolic side of your blood's acid balance. Here's the normal range, what a negative or positive result means, and when it's urgent.
Basophil percentage: normal range and what it means
Basophils are about 1% of white cells, so the percentage is noisy. What's normal, why % and count disagree, and when a lasting rise matters.
Beta-hydroxybutyrate test: normal range, ketosis and DKA
BHB is the main ketone in your blood. Here's the normal range, what ketosis levels look like, how to tell diet ketosis from DKA, and when a high BHB is urgent.
pCO2 blood gas test: normal range, high and low causes
pCO2 shows how well your breathing clears carbon dioxide. Here's the normal range, what high and low results usually mean, and when a result is urgent.
Blood gas pH: normal range, what low or high means
Blood pH is normally 7.35 to 7.45. Here's what a low or high result usually means, how to read it with pCO2 and bicarbonate, and when it's urgent.
pO2 blood gas: normal range, low causes, and what it means
pO2 is the oxygen pressure in your arterial blood: the normal range, what a low result means, how to read it with its neighbors, and when it's urgent.
Blood type (ABO and Rh): what your result means
Your blood type is two results, ABO group and Rh factor. What each type means, how common it is, why labs recheck it, and why Rh matters in pregnancy.
Carboxyhemoglobin test: normal levels and CO poisoning
Carboxyhemoglobin (COHb) is the share of your hemoglobin carrying carbon monoxide. Normal and smoker levels, CO poisoning signs, and when it's urgent.
Direct antiglobulin test (DAT): results explained
The direct Coombs test finds antibody or complement stuck to your red cells. What IgG vs C3d means, why positives without hemolysis are common, when to act.
Direct bilirubin: normal range and what a high result means
Direct bilirubin is the form your liver has already processed. Normal levels, why it runs high, how to read it with ALT and ALP, and when it's urgent.
Eosinophil percentage: what a high or low % means
Eosinophil % is the share of your white cells that are eosinophils. Here's a normal %, why a high one can mislead, and when to read the count instead.
Factor VIII activity: normal range, hemophilia, high levels
Factor VIII helps your blood clot. What a normal level is, how low levels grade hemophilia A, and what a high level means for blood-clot risk.
Fibrinogen blood test: normal range, high and low causes
Fibrinogen is a clotting protein that rises with inflammation. The normal range, what optimizers aim for, why it runs high or low, and when it's urgent.
G6PD test: what your enzyme activity result means
G6PD shields red cells from oxidant damage. What low, intermediate and normal results mean, why women vary, and why a test after hemolysis can mislead.
Haptoglobin blood test: low and high levels explained
Haptoglobin mops up hemoglobin from broken red cells. What's normal, why it runs low or high, how to read it with LDH and bilirubin, and when to worry.
hCG blood test: levels, pregnancy and what results mean
hCG is the pregnancy hormone. Here's a normal level outside pregnancy, how fast it rises, why it can run high, and when a result is urgent.
Hemoglobin A percentage: normal range and what low means
Hemoglobin A is the main adult hemoglobin, usually 95–98% of the total. How the test works, and what a lower share means, from carrier traits to transfusion.
Hemoglobin A2 (HbA2): normal range and beta-thal trait
HbA2 is a minor adult hemoglobin. Here's the normal range, why above 3.5% points to beta-thalassemia trait, and what else can push it up or down.
Fetal hemoglobin (HbF): normal levels and what high means
Hemoglobin F is the hemoglobin you made before birth. Normal levels by age, why it runs high in HPFH and thalassemia, and why more helps in sickle cell.
Hemoglobin S percentage: trait, disease and targets
Hemoglobin S (HbS) percentage is the share of your hemoglobin that is the sickle form. What 0%, under 40% and over 50% mean, and the 30% target.
Immature reticulocyte fraction (IRF): ranges and causes
IRF is the share of your reticulocytes that are brand new. Ranges by analyzer, what high and low mean, and how it flags marrow recovery after chemo.
Indirect bilirubin: normal range and why it runs high
Indirect bilirubin is bilirubin before the liver processes it. Normal ranges, why it runs high (usually Gilbert syndrome), its neighbors and when it's urgent.
LDL particle number (LDL-P): normal, optimal and high
LDL-P counts the LDL particles in your blood. Here's a normal and optimal level, why it runs high when LDL cholesterol looks fine, and how it ties to ApoB.
Lead blood test: normal levels, sources, and when to act
A blood lead test shows recent lead exposure. Here are the CDC and workplace thresholds, the common sources, what low levels are linked to, and when to retest.
Leptin levels: normal range, body fat and resistance
Leptin is made by fat cells, so it tracks body fat and runs higher in women. What's normal, what leptin resistance means, and when the test matters.
Lymphocyte percentage: high, low and what it means
Your lymphocyte percentage is a share of your white count. Here's the normal range, why it can look off when the count is fine, and when it matters.
Mercury blood test: normal levels, fish, and high results
Blood mercury mostly tracks the fish you ate in recent weeks; urine tracks vapor and inorganic mercury. Typical U.S. levels, action levels, and when to worry.
Methemoglobin: normal level, high causes, and when to worry
Methemoglobin is hemoglobin that holds no oxygen. Here's the normal level, what raises it, why pulse oximeters misread it, and when a high level is urgent.
Monocyte percentage: what a high or low result means
Monocyte percentage is the share of your white cells that are monocytes. Here's the normal range, why it can run high while the count is fine, and when to act.
Neutrophil percentage: normal range, high, low and NLR
Neutrophil % is the share of your white cells that are neutrophils. The normal range, why it runs high or low, the count to check, and what NLR adds.
Nucleated red blood cells (NRBC): normal and high results
Nucleated red blood cells are young red cells that belong in the marrow. Why adults should have none, what a positive count means, and when it's urgent.
Omega-3 and omega-6 blood test: reading all 9 results
A whole-blood omega-3 and omega-6 panel reports EPA, DPA, DHA, linoleic and arachidonic acid, two totals and two ratios. Here's what each one means.
PTH blood test: normal range, high causes, and calcium
Parathyroid hormone (PTH) sets your blood calcium. The normal range, what a high or low PTH usually means, why it's read with calcium, and when it's urgent.
Plasma free hemoglobin: normal range and high causes
Plasma free hemoglobin measures hemoglobin loose in your blood. What's normal, how a hard blood draw fakes a high result, and when it's urgent.
Potassium blood test: normal levels, causes, next steps
Potassium keeps your heart and muscles firing. Here's the normal range, the lowest-risk zone, the usual causes of low and high results, and when it's urgent.
Procalcitonin test: normal range, high results, next steps
Procalcitonin rises fast in bacterial infection and sepsis. Here's the normal level, what each cutoff means, how to read it with CRP, and when it's urgent.
Progesterone blood test: normal levels, low and high causes
Progesterone shows whether you ovulated. See normal levels by cycle phase and pregnancy, what a low day-21 result means, and how to read it with LH and FSH.
Prolactin blood test: normal levels and why it runs high
Prolactin is the milk-making hormone. Here's a normal level, the usual reasons it runs high, how to read it with TSH and kidney tests, and when it's urgent.
PT/INR blood test: normal range, high INR, and warfarin
PT and INR measure how fast your blood clots. Here's a normal INR, the target on warfarin, the common reasons it runs high, and when a result is urgent.
PSA blood test: normal by age, free PSA, high causes
PSA is a prostate protein. Here's what's normal for your age, what percent free PSA adds, the usual reasons PSA runs high, and when a result is urgent.
Red blood cell count: normal range, low and high causes
Your RBC count is how many red cells are in your blood. Here is what is normal, what low or high usually means, and how to read it with MCV.
Renin blood test: normal ranges, high and low causes
Renin is the kidney hormone that starts the blood-pressure chain. What's normal, how posture, salt and pills move it, and what high or low renin means.
Reticulocyte count: normal range, high and low causes
Reticulocytes are your newest red blood cells. Here's a normal count, what high and low results mean, how to read it with MCV and ferritin, and when to act.
Reticulocyte hemoglobin (Ret-He): what a low result means
Ret-He shows how much iron reached the red cells your marrow made in the past few days. Normal range, study cutoffs, and why it helps when ferritin misleads.
Rheumatoid factor (RF): normal range and what high means
Rheumatoid factor is an antibody tied to rheumatoid arthritis. What a normal result is, what a positive one usually means, and how to read it with anti-CCP.
Serum osmolality test: normal range, high and low causes
Serum osmolality shows how concentrated your blood is. Here's the normal range, what makes it high or low, how to read it with sodium, and when it's urgent.
SHBG blood test: normal range, low and high causes
SHBG holds testosterone and estrogen in your blood. Here's what's normal, what low or high SHBG usually means, and how to read it with free testosterone.
Sickle cell screen: what a positive or negative means
A sickle cell screen checks blood for hemoglobin S. What a positive or negative result means, when it can be wrong, and which test sorts trait from disease.
LDL particle size: small LDL, pattern B and large HDL
What LDL Small, LDL Medium, LDL Pattern, LDL Peak Size and HDL Large mean, how pattern B is set, and what particle size really adds to heart risk.
Sodium blood test: normal range, low and high causes
Blood sodium mostly tracks water. Here's the normal range, what optimizers aim for, the common causes of low and high sodium, and when it's urgent.
Soluble transferrin receptor test: ranges and causes
sTfR rises when your red-cell factory runs short of iron or speeds up. Normal ranges by lab method, what high and low mean, and how to read it with ferritin.
Thrombin time test: normal range, long results, next steps
The thrombin time checks the last step of clotting. What's normal, why heparin or dabigatran lengthen it, and how labs spot a fibrinogen problem.
Thyroglobulin test: normal range, high Tg and after surgery
Thyroglobulin (Tg) comes from thyroid tissue. Here's the normal range with a thyroid, the targets after thyroid-cancer surgery, and why TgAb matters.
Thyroglobulin antibodies: normal range and high results
Thyroglobulin antibodies (TgAb) signal thyroid autoimmunity. What a normal result is, what a positive one usually means, and how to read it with TSH.
TPO antibodies: normal range, high results and next steps
TPO antibodies show your immune system has targeted your thyroid. What a positive result means, how to read it with TSH, and how fast it changes.
Total IgE blood test: normal range, high levels, causes
Total IgE is the allergy antibody in your blood. Here's a normal level, the usual causes of a high one, the optimal range, and when a low one matters.
Total and non-HDL cholesterol: normal and optimal levels
Total cholesterol counts it all; non-HDL counts the part that builds plaque. Normal and optimal levels, common causes of high results, and how to read them.
Total protein blood test: normal range, low and high causes
Total protein is albumin plus globulins. Here's the normal range, what a high or low result usually means, how to read it with albumin, and when it's urgent.
Total T3 test: normal range, optimal levels, high and low
Total T3 counts all the T3 in your blood, bound and free. Here's the normal and optimal range, why pregnancy and estrogen raise it, and what high or low means.
Total T4 test: normal range, high and low, and pregnancy
Total T4 counts all the thyroxine in your blood, bound and free. Here's the normal range, why pregnancy and estrogen raise it, and when to check free T4.
Transferrin blood test: normal range, high and low causes
Transferrin is the protein that carries iron in your blood. Here's the normal range, why it runs high or low, and how to read it with ferritin and iron.
Transferrin saturation: normal, low, high and optimal
Transferrin saturation is the share of your iron carriers holding iron. Here's what's normal, optimal, what low and high mean, and when to recheck it.
Uric acid blood test: normal levels, high causes, and gout
Uric acid is your body's purine waste. What a normal level is, the targets optimizers aim for, why it runs high, and how it links to gout.
UACR urine test: normal range, high causes, next steps
UACR shows albumin leaking from your kidneys into urine. What's normal, what optimal looks like, the common causes of a high result, and when to act.
Bacteria in urine: what few, moderate and many mean
Bacteria on a urinalysis often mean a contaminated sample or harmless bacteriuria. Here's how it's graded, how it relates to a culture, and when it matters.
Urine bilirubin test: what negative and positive mean
Bilirubin in urine points to the liver or bile ducts. What normal is, the common causes of a positive, how to read it with other tests, and when it's urgent.
Blood in urine test: what a positive result means
A positive urine blood test can mean red cells, free hemoglobin or muscle pigment. What's normal, common causes, the neighbors to check, and when it's urgent.
Urine calcium test: 24-hour normal range and high causes
A 24-hour urine calcium shows how much calcium your kidneys pass. The normal range, why it runs high, the kidney-stone link, and what a low result means.
Urine casts: what hyaline, granular and red cell casts mean
Urine casts are protein plugs molded in the kidney's tubules. A few hyaline casts are usually harmless. Here's what the other types point to.
Urine chloride test: normal range, low and high results
Urine chloride shows how much chloride your kidneys let go. The normal range, what under 20 mmol/L means in metabolic alkalosis, and the urine anion gap.
Urine color and appearance: what your urinalysis means
What yellow, amber, red, brown or cloudy urine means on a urinalysis, why hydration drives most color change, and which colors need prompt care.
Urine creatinine test: normal levels and what they mean
Urine creatinine shows how dilute a sample is, whether a 24-hour collection is complete, and anchors urine ratios. What's normal and why it runs low or high.
Crystals in urine: calcium oxalate, amorphous and more
Most urine crystals are harmless and form after the sample cools. What calcium oxalate and amorphous crystals mean, which types matter, and when to act.
Epithelial cells in urine: what squamous and renal mean
Squamous cells in urine usually mean skin cells got into the sample. Here's what's normal, when renal tubular cells matter, and when to get care.
Urine glucose test: what negative, trace and positive mean
Glucose in urine usually means blood sugar passed your kidneys' limit. What a normal result is, the common causes of a positive, and when it's urgent.
Urine ketones test: what trace, small or large means
Urine ketones show your body burning fat. Here's what negative, trace, small and large mean, why strips miss mild ketosis, and when ketones are urgent.
Urine leukocyte esterase: what a positive result means
Leukocyte esterase flags white blood cells in your urine. Here's what a positive means, the usual causes, how to read it with nitrite, and when to get care.
Urine nitrite test: what positive and negative mean
Nitrite on a urinalysis points to bacteria in the bladder. What a positive result means, why a negative one can miss an infection, and when it's urgent.
Urine pH test: normal range, what low or high means
Urine pH shows how much acid your kidneys are clearing. What's normal, the optimal band, why urine runs acidic or alkaline, and when it matters.
Urine potassium test: 24-hour vs spot, and what it means
Urine potassium shows how much potassium your kidneys let go. Normal 24-hour ranges, spot ratios, and what low or high means when blood potassium is off.
Urine protein test: what trace, 1+ and 2+ mean
Protein on a urinalysis is graded negative to 4+. What each grade means, the common temporary causes, when it points to kidney disease, and when it's urgent.
Urine protein-creatinine ratio: normal range, high causes
UPCR measures all the protein leaking into your urine. What's normal, what 150, 500 and 3,500 mg/g mean, the common causes, and when a high result is urgent.
Red blood cells in urine: what your RBC/hpf count means
Urine red cells are counted per high-power field under a microscope. What's normal, what misshapen cells and casts mean, and the AUA/SUFU workup.
Urine sodium test: normal range, FENa, low and high causes
Urine sodium shows how much salt your kidneys let go. Here's the 24-hour range, spot vs 24-hour tests, FENa, salt targets, and what low or high means.
Urine specific gravity: normal range, high and low causes
Urine specific gravity shows how concentrated your urine is. Here's the normal range, what high and low results usually mean, and when to get care.
Urobilinogen in urine: normal levels, high and low causes
Urine urobilinogen tracks bilirubin's trip from liver to gut and back. Here's the normal 0.2–1.0 range, what high or low means, and when it's urgent.
White blood cells in urine: normal range and causes
White blood cells in urine usually signal infection or inflammation. Here's the normal count, the common causes, what to read beside it, and when it's urgent.
Yeast in urine: contamination, candiduria and next steps
Yeast on a urinalysis can be vaginal yeast in the sample or harmless colonization. Here's who gets true candiduria, how it's confirmed and when it's treated.
VWF activity test: low results, types and the 0.7 ratio
VWF activity shows how well von Willebrand factor grips platelets: the normal range, the activity-to-antigen ratio, the four test types and what low means.
von Willebrand factor antigen: normal range, low results
VWF antigen shows how much von Willebrand factor is in your blood: the normal range, the 2021 von Willebrand disease cutoffs, and why levels swing.
Platelet count: normal range, low and high causes
Platelets help your blood clot. Here's a normal count, why it runs low or high, how to read it with your CBC and ferritin, and when it's urgent.
Phosphorus blood test: normal range, low and high causes
Phosphorus is a mineral shared by your bones, cells and kidneys. Here's the normal range, what low and high results usually mean, and when it's urgent.
MPV blood test: normal range, high and low causes
MPV is the average size of your platelets. What a normal MPV is, what high and low results mean, how to read it with your platelet count, and when to act.
Methylmalonic acid (MMA) test: normal range and high causes
Methylmalonic acid (MMA) shows whether vitamin B12 is working inside your cells. Normal levels, common causes of a high result, and how to read it with B12.
MCV blood test: normal range, low and high causes
MCV is the average size of your red blood cells. Here's what's normal, what a low or high MCV usually means, and how to read it with RDW and B12.
MCHC blood test: normal range, low and high causes
MCHC shows how tightly hemoglobin is packed in your red cells. Normal range, why it runs low or high, how to read it with MCV and RDW, and lab errors.
MCH blood test: normal range, low and high causes
MCH is the average amount of hemoglobin in each red blood cell. Here's the normal range, why it runs low or high, and how to read it with MCV and ferritin.
Magnesium blood test: normal range, low and high causes
Magnesium keeps your nerves, muscles and heart working. Here's the normal range, why it runs low, how to read it with potassium and calcium, and when it's urgent.
LH blood test: normal levels, high and low causes
LH is your brain's signal to the ovaries and testes. See normal LH by sex and cycle phase, what high or low LH usually means, and how to read it.
Lipase test: normal levels, high causes, and next steps
Lipase is the pancreas's fat-digesting enzyme. Here's what a normal level is, what high and low results usually mean, and when a high lipase is urgent.
LDH blood test: normal levels, high causes, and next steps
LDH is an energy enzyme in almost every cell. Here's what a normal level is, why it runs high, how its neighbors find the source, and when it's urgent.
Lactate blood test: normal range, high causes, next steps
Lactate is a fuel your cells make and burn all day. Here's the normal range, what raises it, how to read it with pH and bicarbonate, and when it's urgent.
Iron panel: serum iron, TIBC and saturation explained
An iron panel shows the iron in your blood, the room to carry more and how full the carriers are. Here's what's normal, optimal, and what patterns mean.
Ionized calcium test: normal range, low and high causes
Ionized calcium is the free, active calcium in your blood. Here's the normal range, what low and high levels usually mean, and how to read it with PTH.
Immature granulocytes (IG): normal range and high causes
Immature granulocytes are young white cells released early. Here's a normal level, why IG runs high, how to read it with your CBC, and when it's urgent.
IGF-1 blood test: normal levels by age, low and high causes
IGF-1 tracks growth hormone. Here's the normal range for your age, what optimizers aim for, why it runs low or high, and when to see a specialist.
Globulin and A/G ratio: normal range, high and low causes
Globulin is the non-albumin protein in your blood. Here's a normal globulin and A/G ratio, why they run high or low, and when a result needs follow-up.
GGT blood test: normal levels, high causes, and next steps
GGT is a liver and bile-duct enzyme. What a normal level is, why it runs high, how to read it with ALP, and when a high result is urgent.
FSH blood test: normal levels, high and low causes
FSH is your brain's signal to the ovaries or testes. See normal levels by sex and cycle phase, what high or low FSH usually means, and how to read it.
Folate blood test: normal levels, low causes, next steps
Folate is the B vitamin cells use to build DNA. Here's what a normal level is, why it runs low or high, how to read it with B12, and when to act.
Fasting insulin test: normal, optimal and high levels
Fasting insulin shows how hard your pancreas works to keep blood sugar normal. Here's the normal and optimal range, what high means, and when to worry.
ESR blood test: normal levels, high causes, and next steps
ESR (sed rate) tracks inflammation. Here's a normal ESR by age and sex, the common reasons it runs high, how to read it with CRP, and when it's urgent.
D-dimer test: normal levels, high results, next steps
D-dimer shows your body is breaking down a blood clot. Here's the normal cutoff, the common reasons it runs high, and when a result is urgent.
Cystatin C blood test: normal range, high results, eGFR
Cystatin C is a kidney filtration marker that muscle barely moves. What's normal, what a high result means, how it pairs with creatinine, and when it's urgent.
CK blood test: normal levels, high causes, and next steps
CK is a muscle enzyme. Here's what a normal level is, why a hard workout can push it into the thousands, how to read it with AST and ALT, and when it's urgent.
Cortisol test: normal levels, high and low causes
Cortisol runs on a daily clock. Here's a normal morning level, what high and low results usually mean, how to read it with ACTH, and when low is urgent.
Copper blood test: normal levels, high and low causes
Most copper in your blood rides on one protein. Here's the normal range, the optimal ladder, why copper runs high or low, and how to read it with zinc.
Chloride blood test: normal range, low and high causes
Chloride is sodium's salt partner. Here's the normal range, what low or high chloride usually means, how to read it with sodium and CO2, and when to act.
Ceruloplasmin test: normal range, low and high results
Ceruloplasmin carries most of your blood's copper. What a normal level is, what low and high results usually mean, and when to think of Wilson disease.
Troponin test: normal levels, high results, next steps
Troponin is the blood test for heart-muscle injury. Here's what's normal on each test, what a high result usually means, and when it's an emergency.
Calcium blood test: normal range, high and low causes
Blood calcium is tightly controlled. Here's the normal range, the usual reasons it runs high or low, how to read it with PTH and albumin, and when it's urgent.
C-peptide test: normal levels, high and low causes
C-peptide shows how much insulin your pancreas makes. Here's the normal range, what high and low results usually mean, and how to read it with blood sugar.
BUN blood test: normal levels, high causes, and next steps
BUN measures urea, the waste your liver makes from protein. Here's a normal level, why it runs high or low, and how to read it next to creatinine.
BNP and NT-proBNP: normal levels, high causes, next steps
BNP and NT-proBNP rise when the heart is strained. What's normal by age, what else raises them, how to read them with other tests, and when it's urgent.
Bilirubin blood test: normal levels and why it runs high
Bilirubin comes from old red blood cells. Normal levels, why it runs high (often Gilbert syndrome), how to read it next to ALT and ALP, and when it's urgent.
CO2 blood test (bicarbonate): normal range, low and high
The CO2 on your metabolic panel is bicarbonate. Here's the normal range, what low or high usually means, how to read it with chloride, and when it's urgent.
AMH blood test: normal levels by age and what they mean
AMH tracks how many eggs your ovaries have left. See normal levels by age, what low and high results usually mean, and what AMH predicts.
Anion gap blood test: normal range, high and low causes
The anion gap is a quick math check on your electrolytes. What's normal, why it runs high or low, how to read it with bicarbonate and albumin, and when to act.
Amylase blood test: normal range, high and low causes
Amylase is a starch-digesting enzyme from your pancreas and salivary glands. What's normal, why it runs high or low, and when a high result is urgent.
aPTT blood test: normal range, long and short results
aPTT times how fast your plasma clots. Here's the normal range, what a long or short result usually means, how to read it with PT, and when it's urgent.
Absolute neutrophil count (ANC): normal, low and high
ANC counts the infection-fighting neutrophils in your blood. The normal range, why it runs low or high, how to read it with your CBC, and when to act.
Absolute monocyte count: normal range, highs and lows
Monocytes are white blood cells that clean up and call in help. Here's a normal count, why it runs high or low, and when a result needs a closer look.
Absolute lymphocyte count: normal, low, high and optimal
Lymphocytes are your B, T and NK immune cells. Here's a normal absolute count, what a low or high result usually means, and when it needs a closer look.
Absolute eosinophil count (AEC): normal, high and low
Eosinophils are white cells tied to allergy and parasites. Here's a normal count, the usual causes of a high one, the optimal range, and when it's urgent.
Absolute basophil count: normal range, highs and lows
Basophils are the rarest white blood cell. Here's a normal basophil count, what a high or low result usually means, and when a high count needs a closer look.
White blood cell count: normal range, high and low causes
Your WBC counts the immune cells in your blood. Here's the normal and optimal range, why it runs high or low, how to read the differential, and when to act.
Hemoglobin and hematocrit: normal ranges and what they mean
Hemoglobin carries oxygen; hematocrit is the share of your blood that's red cells. Here's what's normal, what low or high usually means, and what's urgent.
Albumin blood test: normal range, low causes, optimal
Albumin is the main protein in your blood. Here's the normal range, what optimizers aim for, why it usually runs low, and how to read it with its neighbors.
ALP blood test: normal levels, high and low causes
ALP is an enzyme from your liver and bones. Here's a normal level, why it runs high or low, how GGT tells liver from bone, and when it's urgent.
ALT blood test: normal levels, high causes, and next steps
ALT is a liver enzyme. Here's what a normal level is, the most common reasons it runs high, how to read it with AST and ALP, and when a high result is urgent.
ApoB test: normal and optimal levels, and what high means
ApoB counts the particles that clog arteries. Here's a normal level, the optimal targets, why it can be high when LDL looks fine, and what moves it.
AST blood test: normal levels, high causes, and next steps
AST is an enzyme in liver, muscle and red blood cells. What a normal level is, why it runs high, how to read it with ALT and CK, and when it's urgent.
DHEA-S blood test: normal by age, high and low causes
DHEA-S is an adrenal hormone that falls with age. Here's the normal range by age and sex, what high and low levels usually mean, and when it's urgent.
eGFR and creatinine: normal ranges, low eGFR causes
eGFR shows how well your kidneys filter, and it's calculated from creatinine. What's normal, what a low eGFR usually means, and when it's urgent.
Estradiol blood test: normal levels, high and low causes
Estradiol (E2) is your main estrogen. See normal levels for men and women, what high or low results usually mean, and how to read E2 with FSH and LH.
Fasting glucose test: normal, optimal, and high levels
Fasting glucose shows how your body holds blood sugar overnight. Here's what's normal, what's optimal, why it runs high or low, and when a result is urgent.
Ferritin blood test: normal levels, low and high causes
Ferritin shows how full your iron stores are. Here's what's normal and optimal, why it runs low or high, how to read it with iron saturation, and when to act.
Free T3 test: normal range, optimal levels, high and low
Free T3 is the active thyroid hormone. Here's the normal and optimal range, what high or low usually means, and how to read it with TSH and free T4.
Free T4 blood test: normal range, high and low causes
Free T4 is the unbound thyroid hormone in your blood. Here's what a normal level is, what optimizers aim for, why it runs low or high, and when it's urgent.
A1C (HbA1c) test: normal, optimal and high levels
A1C shows your average blood sugar over about 3 months. Here's what's normal, what optimal looks like, why it runs high or low, and when to get care.
HDL cholesterol: normal levels, low and high causes
HDL is the "good" cholesterol. Here's what a normal level is, why it runs low, when a high HDL stops helping, and how to read it with triglycerides.
Homocysteine test: normal levels, high causes, next steps
Homocysteine is an amino acid that B vitamins and your kidneys clear. What is normal, what optimizers aim for, why it runs high, and how to read it with B12.
CRP and hs-CRP blood test: normal levels and high causes
CRP is your body's inflammation signal. Here's what a normal CRP and hs-CRP is, the common reasons it runs high, and when a high result needs care.
LDL cholesterol: normal and optimal levels, high causes
LDL carries cholesterol into artery walls. Here's what a normal and optimal LDL is, why it runs high, how to read it with ApoB and Lp(a), and when to act.
Lp(a) blood test: normal levels, high risk, next steps
Lp(a) is an inherited cholesterol particle. Here's a normal level, the optimal targets, what a high result means for heart risk, and how to read the units.
Omega-3 index: normal levels, targets, and what moves it
The omega-3 index is the share of EPA and DHA in your red blood cells. Here's what's typical, why 8% is the usual target, and what raises it.
RDW blood test: normal range, high causes, next steps
RDW measures how much your red blood cells vary in size. Here's what's normal, what a high RDW usually means, and how to read it with MCV and ferritin.
Testosterone test: normal levels, low T causes, next steps
What a normal testosterone level is for men and women, the optimal ranges people aim for, the most common causes of low T, and when a result is urgent.
Triglycerides: normal levels, high causes, and next steps
Triglycerides are the fat in your blood. Here's what a normal level is, why they run high, how to read them with HDL and LDL, and when a result is urgent.
TSH blood test: normal range, high and low causes
TSH is your pituitary's signal to your thyroid. Here's what a normal TSH is, what optimizers aim for, why it runs high or low, and when it's urgent.
Vitamin B12 test: what low, normal and high levels mean
Vitamin B12 keeps your nerves and red blood cells healthy. Here's a normal level, why it runs low, how MMA settles a borderline result, and when to act fast.
Vitamin D blood test: normal, optimal, low and high levels
Your vitamin D test measures 25-hydroxyvitamin D. What is normal, what optimizers aim for, why it runs low or high, and when a result is urgent.