THE LIBBY JOURNALGuides & reference · What your records are telling youOCT 2026 · 48 ENTRIES

Your health record,made legible.

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Guides & pillars

How to read your results, own your record, and make sense of the whole picture.

Featured · Start here · CK · 18 min

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.

Start here · cortisol · 18 min

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.

Start here · copper · 18 min

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.

Start here · chloride · 19 min

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.

Start here · ceruloplasmin · 17 min

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.

Start here · troponin · 22 min

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.

Start here · calcium · 18 min

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.

Start here · C-peptide · 19 min

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.

Start here · BUN · 19 min

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.

Start here · BNP · 18 min

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.

Start here · bilirubin · 19 min

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.

Start here · CO2 · 18 min

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.

Start here · AMH · 19 min

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.

Start here · anion gap · 18 min

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.

Start here · amylase · 17 min

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.

Start here · aPTT · 19 min

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.

Start here · absolute neutrophil count · 19 min

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.

Start here · absolute monocyte count · 18 min

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.

Start here · absolute lymphocyte count · 20 min

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.

Start here · eosinophils · 19 min

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.

Start here · basophils · 18 min

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.

Start here · white blood cells · 20 min

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.

Start here · hemoglobin · 20 min

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.

Start here · albumin · 18 min

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.

Updated September 24, 2026
Start here · ALP · 20 min

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.

Updated September 24, 2026
Start here · ALT · 15 min

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.

Updated September 24, 2026
Start here · ApoB · 18 min

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.

Updated September 24, 2026
Start here · AST · 17 min

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.

Updated September 24, 2026
Start here · DHEA-S · 19 min

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.

Updated September 24, 2026
Start here · eGFR · 20 min

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.

Updated September 24, 2026
Start here · estradiol · 20 min

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.

Updated September 24, 2026
Start here · fasting glucose · 20 min

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.

Updated September 24, 2026
Start here · ferritin · 20 min

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.

Updated September 24, 2026
Start here · free T3 · 18 min

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.

Updated September 24, 2026
Start here · free T4 · 20 min

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.

Updated September 24, 2026
Start here · HbA1c · 17 min

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.

Updated September 24, 2026
Start here · HDL cholesterol · 20 min

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.

Updated September 24, 2026
Start here · homocysteine · 18 min

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.

Updated September 24, 2026
Start here · CRP · 20 min

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.

Updated September 24, 2026
Start here · LDL cholesterol · 18 min

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.

Updated September 24, 2026
Start here · Lp(a) · 21 min

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.

Updated September 24, 2026
Start here · omega-3 index · 19 min

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.

Updated September 24, 2026
Start here · RDW · 18 min

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.

Updated September 24, 2026
Start here · testosterone · 21 min

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.

Updated September 24, 2026
Start here · triglycerides · 16 min

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.

Updated September 24, 2026
Start here · TSH · 18 min

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.

Updated September 24, 2026
Start here · vitamin B12 · 19 min

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.

Updated September 24, 2026
Start here · vitamin D · 19 min

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.

Updated September 24, 2026
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