THE LIBBY JOURNALGuides & reference · What your records are telling youNOV 2026 · 174 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 · getting started · 1 min
Start here: what Libby is, and where to begin in the Library
New to Libby? What it does today, what's coming, and the guides worth reading first: owning your records and reading your results.
- Start here · own your data · 2 min
What changes when all your health records are in one place
Your health data is scattered. Your body is not. What becomes possible when every lab result and record sits in one place that belongs to you.
- Start here · own your data · 3 min
From HIPAA to TEFCA: how your health records became yours to request
The legal right to your records is broad, and since late 2023 a national network can deliver them. How the law got there, and how you can get your records today.
- Start here · own your data · 3 min
Vision: from your health record to a health system that works for you
Libby starts as the record, because everything we want to build needs something real to reason from. Then an agent that acts for you, then better medicine.
Reference
Marker glossary
One clear explainer per marker — what it is and how to read your level.
0–9
A
- A1C (HbA1c) test:normal, optimal and high levels
- Absolute basophil count:normal range, highs and lows
- Absolute eosinophil count (AEC):normal, high and low
- Absolute lymphocyte count:normal, low, high and optimal
- Absolute monocyte count:normal range, highs and lows
- Absolute neutrophil count (ANC):normal, low and high
- ACTH blood test:normal range, high and low causes
- Albumin blood test:normal range, low causes, optimal
- Aldosterone test:normal levels, renin ratio and causes
- ALP blood test:normal levels, high and low causes
- ALT blood test:normal levels, high causes, and next steps
- AMH blood test:normal levels by age and what they mean
- Ammonia blood test:normal range, high causes, next steps
- Amylase blood test:normal range, high and low causes
- ANA test:positive results, titers and patterns explained
- Anion gap blood test:normal range, high and low causes
- Anti-CCP test:what a positive result means for RA
- Anti-Xa test:target levels for heparin, apixaban and more
- ApoB test:normal and optimal levels, and what high means
- aPTT blood test:normal range, long and short results
- AST blood test:normal levels, high causes, and next steps
B
- Bacteria in urine:what few, moderate and many mean
- Band neutrophils (bands):what a high count means
- Base excess blood test:normal range, low and high causes
- Basophil percentage:normal range and what it means
- Beta-hydroxybutyrate test:normal range, ketosis and DKA
- Bilirubin blood test:normal levels and why it runs high
- Blood gas pH:normal range, what low or high means
- Blood in urine test:what a positive result means
- Blood type (ABO and Rh):what your result means
- BNP and NT-proBNP:normal levels, high causes, next steps
- BUN blood test:normal levels, high causes, and next steps
C
- C-peptide test:normal levels, high and low causes
- Calcium blood test:normal range, high and low causes
- Carboxyhemoglobin test:normal levels and CO poisoning
- Ceruloplasmin test:normal range, low and high results
- Chloride blood test:normal range, low and high causes
- CK blood test:normal levels, high causes, and next steps
- CO2 blood test (bicarbonate):normal range, low and high
- Copper blood test:normal levels, high and low causes
- Cortisol test:normal levels, high and low causes
- CRP and hs-CRP blood test:normal levels and high causes
- Crystals in urine:calcium oxalate, amorphous and more
- Cystatin C blood test:normal range, high results, eGFR
D
E
F
- Factor VIII activity:normal range, hemophilia, high levels
- Fasting glucose test:normal, optimal, and high levels
- Fasting insulin test:normal, optimal and high levels
- Ferritin blood test:normal levels, low and high causes
- Fetal hemoglobin (HbF):normal levels and what high means
- Fibrinogen blood test:normal range, high and low causes
- Folate blood test:normal levels, low causes, next steps
- Free T3 test:normal range, optimal levels, high and low
- Free T4 blood test:normal range, high and low causes
- FSH blood test:normal levels, high and low causes
G
H
- Haptoglobin blood test:low and high levels explained
- hCG blood test:levels, pregnancy and what results mean
- HDL cholesterol:normal levels, low and high causes
- Hemoglobin A percentage:normal range and what low means
- Hemoglobin A2 (HbA2):normal range and beta-thal trait
- Hemoglobin and hematocrit:normal ranges and what they mean
- Hemoglobin S percentage:trait, disease and targets
- Homocysteine test:normal levels, high causes, next steps
I
- IGF-1 blood test:normal levels by age, low and high causes
- Immature granulocytes (IG):normal range and high causes
- Immature reticulocyte fraction (IRF):ranges and causes
- Indirect bilirubin:normal range and why it runs high
- Ionized calcium test:normal range, low and high causes
- Iron panel:serum iron, TIBC and saturation explained
L
- Lactate blood test:normal range, high causes, next steps
- LDH blood test:normal levels, high causes, and next steps
- LDL cholesterol:normal and optimal levels, high causes
- LDL particle number (LDL-P):normal, optimal and high
- LDL particle size:small LDL, pattern B and large HDL
- Lead blood test:normal levels, sources, and when to act
- Leptin levels:normal range, body fat and resistance
- LH blood test:normal levels, high and low causes
- Lipase test:normal levels, high causes, and next steps
- Lp(a) blood test:normal levels, high risk, next steps
- Lymphocyte percentage:high, low and what it means
M
- Magnesium blood test:normal range, low and high causes
- MCH blood test:normal range, low and high causes
- MCHC blood test:normal range, low and high causes
- MCV blood test:normal range, low and high causes
- Mercury blood test:normal levels, fish, and high results
- Methemoglobin:normal level, high causes, and when to worry
- Methylmalonic acid (MMA) test:normal range and high causes
- Monocyte percentage:what a high or low result means
- MPV blood test:normal range, high and low causes
N
O
P
- pCO2 blood gas test:normal range, high and low causes
- Phosphorus blood test:normal range, low and high causes
- Plasma free hemoglobin:normal range and high causes
- Platelet count:normal range, low and high causes
- pO2 blood gas:normal range, low causes, and what it means
- Potassium blood test:normal levels, causes, next steps
- Procalcitonin test:normal range, high results, next steps
- Progesterone blood test:normal levels, low and high causes
- Prolactin blood test:normal levels and why it runs high
- PSA blood test:normal by age, free PSA, high causes
- PT/INR blood test:normal range, high INR, and warfarin
- PTH blood test:normal range, high causes, and calcium
R
- RDW blood test:normal range, high causes, next steps
- Red blood cell count:normal range, low and high causes
- Red blood cells in urine:what your RBC/hpf count means
- Renin blood test:normal ranges, high and low causes
- Reticulocyte count:normal range, high and low causes
- Reticulocyte hemoglobin (Ret-He):what a low result means
- Rheumatoid factor (RF):normal range and what high means
S
T
- Testosterone test:normal levels, low T causes, next steps
- Thrombin time test:normal range, long results, next steps
- Thyroglobulin antibodies:normal range and high results
- Thyroglobulin test:normal range, high Tg and after surgery
- Total and non-HDL cholesterol:normal and optimal levels
- Total IgE blood test:normal range, high levels, causes
- Total protein blood test:normal range, low and high causes
- Total T3 test:normal range, optimal levels, high and low
- Total T4 test:normal range, high and low, and pregnancy
- TPO antibodies:normal range, high results and next steps
- Transferrin blood test:normal range, high and low causes
- Transferrin saturation:normal, low, high and optimal
- Triglycerides:normal levels, high causes, and next steps
- Troponin test:normal levels, high results, next steps
- TSH blood test:normal range, high and low causes
U
- UACR urine test:normal range, high causes, next steps
- Uric acid blood test:normal levels, high causes, and gout
- Urine bilirubin test:what negative and positive mean
- Urine calcium test:24-hour normal range and high causes
- Urine casts:what hyaline, granular and red cell casts mean
- Urine chloride test:normal range, low and high results
- Urine color and appearance:what your urinalysis means
- Urine creatinine test:normal levels and what they mean
- Urine glucose test:what negative, trace and positive mean
- Urine ketones test:what trace, small or large means
- Urine leukocyte esterase:what a positive result means
- Urine nitrite test:what positive and negative mean
- Urine pH test:normal range, what low or high means
- Urine potassium test:24-hour vs spot, and what it means
- Urine protein test:what trace, 1+ and 2+ mean
- Urine protein-creatinine ratio:normal range, high causes
- Urine sodium test:normal range, FENa, low and high causes
- Urine specific gravity:normal range, high and low causes
- Urobilinogen in urine:normal levels, high and low causes
V
W
Y
Index
By body system
The guides shelved by what they measure, with the topic pages for each. A guide can sit on more than one shelf.
Blood count
23 guides- Absolute basophil count
- Absolute eosinophil count (AEC)
- Absolute lymphocyte count
- Absolute monocyte count
- Absolute neutrophil count (ANC)
- Band neutrophils (bands)
- Basophil percentage
- Eosinophil percentage
- Hemoglobin and hematocrit
- Immature granulocytes (IG)
- Lymphocyte percentage
- MCH blood test
- MCHC blood test
- MCV blood test
- Monocyte percentage
- MPV blood test
- Neutrophil percentage
- Nucleated red blood cells (NRBC)
- Platelet count
- RDW blood test
- Red blood cell count
- Reticulocyte count
- White blood cell count
Anemia, iron & hemoglobin
25 guides- Blood type (ABO and Rh)
- Carboxyhemoglobin test
- Direct antiglobulin test (DAT)
- Ferritin blood test
- Fetal hemoglobin (HbF)
- G6PD test
- Haptoglobin blood test
- Hemoglobin A percentage
- Hemoglobin A2 (HbA2)
- Hemoglobin and hematocrit
- Hemoglobin S percentage
- Immature reticulocyte fraction (IRF)
- Iron panel
- LDH blood test
- MCV blood test
- Methemoglobin
- Plasma free hemoglobin
- RDW blood test
- Red blood cell count
- Reticulocyte count
- Reticulocyte hemoglobin (Ret-He)
- Sickle cell screen
- Soluble transferrin receptor test
- Transferrin blood test
- Transferrin saturation
Clotting & bleeding
9 guidesHeart & cholesterol
13 guidesBlood sugar & metabolism
11 guidesKidneys
13 guidesUrine tests
22 guides- Bacteria in urine
- Blood in urine test
- Crystals in urine
- Epithelial cells in urine
- Red blood cells in urine
- Urine bilirubin test
- Urine calcium test
- Urine casts
- Urine chloride test
- Urine color and appearance
- Urine creatinine test
- Urine glucose test
- Urine ketones test
- Urine leukocyte esterase
- Urine nitrite test
- Urine pH test
- Urine protein test
- Urine sodium test
- Urine specific gravity
- Urobilinogen in urine
- White blood cells in urine
- Yeast in urine
Liver & pancreas
16 guidesElectrolytes & blood gas
20 guides- Anion gap blood test
- Base excess blood test
- Blood gas pH
- Calcium blood test
- Chloride blood test
- CO2 blood test (bicarbonate)
- Ionized calcium test
- Magnesium blood test
- Methemoglobin
- pCO2 blood gas test
- Phosphorus blood test
- pO2 blood gas
- Potassium blood test
- PTH blood test
- Serum osmolality test
- Sodium blood test
- Urine chloride test
- Urine color and appearance
- Urine potassium test
- Urine specific gravity
Thyroid
8 guidesHormones & fertility
18 guidesInflammation & immunity
8 guidesVitamins, minerals & metals
12 guidesYour records
4 guidesIndex
Browse by topic
- 24-hour urine
- 24-hour urine protein
- 25-hydroxyvitamin D
- A/G ratio
- A1C
- ABO blood group
- absolute lymphocyte count
- absolute monocyte count
- absolute neutrophil count
- acid-base
- acid-base balance
- ACTH
- adrenal glands
- adrenal hormones
- albumin
- albuminuria
- aldosterone
- alkaline phosphatase
- allergy testing
- ALP
- ALT
- AMH
- ammonia
- amorphous sediment
- amylase
- ANA
- anemia
- anion gap
- anti-CCP
- anti-Xa
- antinuclear antibodies
- ApoB
- aPTT
- AST
- autoimmune
- B vitamins
- bacteria in urine
- bacteriuria
- band neutrophils
- base excess
- basophil percentage
- basophils
- beta-hydroxybutyrate
- bicarbonate
- bilirubin
- biomarker guides
- bleeding disorders
- blood clots
- blood gas
- blood lead
- blood pH
- blood pressure
- blood sugar
- blood thinners
- blood type
- BNP
- bone health
- bone marrow
- BUN
- C-peptide
- calcium
- calcium oxalate
- Candida
- candiduria
- carbon monoxide
- carboxyhemoglobin
- CBC
- CBC differential
- ceruloplasmin
- chloride
- cholesterol
- CHr
- CK
- clotting
- clotting tests
- CO2
- coagulation
- COHb
- complete blood count
- Coombs test
- copper
- cortisol
- creatine kinase
- creatinine
- CRP
- cystatin C
- D-dimer
- DHEA-S
- direct antiglobulin test
- direct bilirubin
- eGFR
- electrolytes
- eosinophils
- epithelial cells
- ESR
- estradiol
- factor VIII
- fasting glucose
- fasting insulin
- fatty acids
- FENa
- ferritin
- fertility
- fetal hemoglobin
- fibrinogen
- folate
- folic acid
- free PSA
- free T3
- free T4
- FSH
- G6PD
- G6PD deficiency
- getting started
- GGT
- globulin
- gout
- growth hormone
- haptoglobin
- Hashimoto's
- HbA1c
- HbF
- hCG
- HDL cholesterol
- heart failure
- heart health
- heavy metals
- hematocrit
- hematuria
- hemoglobin
- hemoglobin A
- hemoglobin A2
- hemoglobin electrophoresis
- hemoglobin S
- hemolysis
- hemophilia
- heparin
- high blood pressure
- homocysteine
- hormones
- hs-CRP
- hyaline casts
- hydration
- hyperammonemia
- hypercalciuria
- hyperparathyroidism
- IgE
- IGF-1
- immature granulocytes
- immature reticulocyte fraction
- immune system
- indirect bilirubin
- inflammation
- insulin
- insulin resistance
- ionized calcium
- IRF
- iron
- iron deficiency
- iron panel
- iron tests
- ketones
- ketosis
- kidney
- kidney function
- kidney health
- kidney stones
- kidney tests
- lab results
- lactate
- lactate dehydrogenase
- lactic acid
- LDH
- LDL cholesterol
- LDL particle number
- LDL pattern
- LDL-P
- lead
- left shift
- leptin
- leptin resistance
- leukocyte esterase
- LH
- lipase
- lipid panel
- lipoprotein particle size
- lipoprotein(a)
- liver
- liver enzymes
- liver health
- liver tests
- Lp(a)
- lupus
- lymphocyte percentage
- lymphocytes
- magnesium
- MCH
- MCHC
- MCV
- medical records
- menopause
- mercury
- methemoglobin
- methemoglobinemia
- methylmalonic acid
- microscopic hematuria
- monocyte percentage
- monocytes
- MPV
- muscle enzymes
- neutrophil percentage
- neutrophil-to-lymphocyte ratio
- neutrophils
- non-HDL cholesterol
- NRBC
- NT-proBNP
- nucleated red blood cells
- omega-3
- omega-3 index
- omega-6
- osmolal gap
- ovarian reserve
- own your data
- oxygen
- pancreas
- pancreatitis
- PaO2
- parathyroid
- parathyroid hormone
- pCO2
- PCT
- personal health record
- phosphate
- phosphorus
- pituitary
- plasma free hemoglobin
- Platelet count
- platelets
- pO2
- potassium
- prediabetes
- pregnancy
- primary aldosteronism
- procalcitonin
- progesterone
- prolactin
- prostate
- proteinuria
- prothrombin time
- PSA
- PT/INR
- PTH
- PTT
- pyuria
- RBC
- RDW
- red blood cell count
- red blood cell indices
- red blood cells
- renin
- Ret-He
- reticulocyte count
- reticulocyte hemoglobin
- reticulocytes
- Rh factor
- rheumatoid arthritis
- rheumatoid factor
- salt intake
- sepsis
- serum osmolality
- SHBG
- sickle cell disease
- sickle cell screen
- sickle cell trait
- small LDL
- sodium
- soluble transferrin receptor
- squamous epithelial cells
- sTfR
- TEFCA
- testosterone
- TgAb
- thalassemia
- thrombin time
- thyroglobulin
- thyroglobulin antibodies
- thyroid
- thyroid cancer
- thyroid tests
- total cholesterol
- total protein
- total T3
- total T4
- TPO antibodies
- trace minerals
- transferrin
- transferrin saturation
- triglycerides
- troponin
- TSAT
- TSH
- UACR
- UPCR
- urate
- uric acid
- urinalysis
- urinary tract infection
- urine appearance
- urine bilirubin
- urine blood
- urine calcium
- urine casts
- urine chloride
- urine color
- urine creatinine
- urine crystals
- urine glucose
- urine ketones
- urine nitrite
- urine pH
- urine potassium
- urine protein
- urine red blood cells
- urine sodium
- urine specific gravity
- urine tests
- urine white blood cells
- urobilinogen
- vitamin B12
- vitamin B9
- vitamin D
- von Willebrand factor
- VWF activity
- VWF antigen
- warfarin
- white blood cell differential
- white blood cells
- Wilson disease
- yeast in urine