NBME Lab Values 2026: The Normal Lab Values Sheet
Written by Dr Zartasha Ali, MBBS, FCPS (Medicine). Reviewed by Dr Ammar Hussain, MBBS, FCPS (Pediatrics), MRCPCH.
NBME lab values are the normal reference ranges you can open during every USMLE exam and NBME practice test. The table below holds every value from the official USMLE Laboratory Values table, in US units and SI units. Type a test name to find it, or print the whole sheet.
No test matches that search. Try a shorter word, such as "iron" or "T4".
Serum: electrolytes and general chemistry
| Test | US units | SI units |
|---|---|---|
| Sodium (Na+) | 136-146 mEq/L | 136-146 mmol/L |
| Potassium (K+) | 3.5-5.0 mEq/L | 3.5-5.0 mmol/L |
| Chloride (Cl-) | 95-105 mEq/L | 95-105 mmol/L |
| Bicarbonate (HCO3-) | 22-28 mEq/L | 22-28 mmol/L |
| Urea nitrogen (BUN) | 7-18 mg/dL | 2.5-6.4 mmol/L |
| Creatinine | 0.6-1.2 mg/dL | 53-106 µmol/L |
| Glucose | Fasting: 70-100 mg/dL | Fasting: 3.8-5.6 mmol/L |
| Random, non-fasting: <140 mg/dL | Random, non-fasting: <7.77 mmol/L | |
| Calcium | 8.4-10.2 mg/dL | 2.1-2.6 mmol/L |
| Magnesium (Mg2+) | 1.5-2.0 mg/dL | 0.75-1.0 mmol/L |
| Phosphorus (inorganic) | 3.0-4.5 mg/dL | 1.0-1.5 mmol/L |
Serum: liver tests and proteins
| Test | US units | SI units |
|---|---|---|
| Alanine aminotransferase (ALT) | 10-40 U/L | 10-40 U/L |
| Aspartate aminotransferase (AST) | 12-38 U/L | 12-38 U/L |
| Alkaline phosphatase | 25-100 U/L | 25-100 U/L |
| Bilirubin | Total: 0.1-1.0 mg/dL | Total: 2-17 µmol/L |
| Direct: 0.0-0.3 mg/dL | Direct: 0-5 µmol/L | |
| Proteins, total | 6.0-7.8 g/dL | 60-78 g/L |
| Albumin | 3.5-5.5 g/dL | 35-55 g/L |
| Globulin | 2.3-3.5 g/dL | 23-35 g/L |
Serum: enzymes and other tests
| Test | US units | SI units |
|---|---|---|
| Amylase | 25-125 U/L | 25-125 U/L |
| Lipase | 13-60 U/L | 13-60 U/L |
| Creatinine clearance | Male: 97-137 mL/min | Male: 97-137 mL/min |
| Female: 88-128 mL/min | Female: 88-128 mL/min | |
| Creatine kinase (CK) | Male: 25-90 U/L | Male: 25-90 U/L |
| Female: 10-70 U/L | Female: 10-70 U/L | |
| Lactate dehydrogenase (LDH) | 45-200 U/L | 45-200 U/L |
| Osmolality, serum | 275-295 mOsmol/kg H2O | 275-295 mOsmol/kg H2O |
| Troponin I | ≤0.04 ng/mL | ≤0.04 µg/L |
| Uric acid | 3.0-8.2 mg/dL | 0.18-0.48 mmol/L |
Serum: lipids
| Test | US units | SI units |
|---|---|---|
| Cholesterol, total | Normal: <200 mg/dL | Normal: <5.2 mmol/L |
| High: >240 mg/dL | High: >6.2 mmol/L | |
| HDL cholesterol | 40-60 mg/dL | 1.0-1.6 mmol/L |
| LDL cholesterol | <160 mg/dL | <4.2 mmol/L |
| Triglycerides | Normal: <150 mg/dL | Normal: <1.70 mmol/L |
| Borderline: 151-199 mg/dL | Borderline: 1.71-2.25 mmol/L |
Serum: iron studies
| Test | US units | SI units |
|---|---|---|
| Ferritin | Male: 20-250 ng/mL | Male: 20-250 µg/L |
| Female: 10-120 ng/mL | Female: 10-120 µg/L | |
| Iron | Male: 65-175 µg/dL | Male: 11.6-31.3 µmol/L |
| Female: 50-170 µg/dL | Female: 9.0-30.4 µmol/L | |
| Total iron-binding capacity (TIBC) | 250-400 µg/dL | 44.8-71.6 µmol/L |
| Transferrin | 200-360 mg/dL | 2.0-3.6 g/L |
Serum: hormones
| Test | US units | SI units |
|---|---|---|
| Follicle-stimulating hormone (FSH) | Male: 4-25 mIU/mL | Male: 4-25 IU/L |
| Female, premenopause: 4-30 mIU/mL | Female, premenopause: 4-30 IU/L | |
| Female, midcycle peak: 10-90 mIU/mL | Female, midcycle peak: 10-90 IU/L | |
| Female, postmenopause: 40-250 mIU/mL | Female, postmenopause: 40-250 IU/L | |
| Luteinizing hormone (LH) | Male: 6-23 mIU/mL | Male: 6-23 IU/L |
| Female, follicular phase: 5-30 mIU/mL | Female, follicular phase: 5-30 IU/L | |
| Female, midcycle: 75-150 mIU/mL | Female, midcycle: 75-150 IU/L | |
| Female, postmenopause: 30-200 mIU/mL | Female, postmenopause: 30-200 IU/L | |
| Growth hormone, arginine stimulation | Fasting: <5 ng/mL | Fasting: <5 µg/L |
| Provocative stimuli: >7 ng/mL | Provocative stimuli: >7 µg/L | |
| Prolactin (hPRL) | Male: <17 ng/mL | Male: <17 µg/L |
| Female: <25 ng/mL | Female: <25 µg/L | |
| Cortisol | 0800 h: 5-23 µg/dL | 0800 h: 138-635 nmol/L |
| 1600 h: 3-15 µg/dL | 1600 h: 82-413 nmol/L | |
| 2000 h: <50% of 0800 h | 2000 h: Fraction of 0800 h: <0.50 | |
| TSH | 0.4-4.0 µU/mL | 0.4-4.0 mIU/L |
| Triiodothyronine (T3), RIA | 100-200 ng/dL | 1.5-3.1 nmol/L |
| Triiodothyronine (T3) resin uptake | 25%-35% | 0.25-0.35 |
| Thyroxine (T4) | 5-12 µg/dL | 64-155 nmol/L |
| Free T4 | 0.9-1.7 ng/dL | 12.0-21.9 pmol/L |
| Thyroidal iodine (123I) uptake | 8%-30% of administered dose/24 h | 0.08-0.30/24 h |
| Intact PTH | 10-60 pg/mL | 10-60 ng/L |
| 17-Hydroxycorticosteroids | Male: 3.0-10.0 mg/24 h | Male: 8.2-27.6 µmol/24 h |
| Female: 2.0-8.0 mg/24 h | Female: 5.5-22.0 µmol/24 h | |
| 17-Ketosteroids, total | Male: 8-20 mg/24 h | Male: 28-70 µmol/24 h |
| Female: 6-15 mg/24 h | Female: 21-52 µmol/24 h |
Serum: immunoglobulins
| Test | US units | SI units |
|---|---|---|
| IgA | 76-390 mg/dL | 0.76-3.90 g/L |
| IgE | 0-380 IU/mL | 0-380 kIU/L |
| IgG | 650-1500 mg/dL | 6.5-15.0 g/L |
| IgM | 50-300 mg/dL | 0.5-3.0 g/L |
Arterial blood gases (room air)
| Test | US units | SI units |
|---|---|---|
| PO2 | 75-105 mm Hg | 10.0-14.0 kPa |
| PCO2 | 33-45 mm Hg | 4.4-5.9 kPa |
| pH | 7.35-7.45 | [H+] 36-44 nmol/L |
Cerebrospinal fluid
| Test | US units | SI units |
|---|---|---|
| Cell count, CSF | 0-5/mm³ | 0-5 × 10⁶/L |
| Chloride, CSF | 118-132 mEq/L | 118-132 mmol/L |
| Gamma globulin, CSF | 3%-12% total proteins | 0.03-0.12 |
| Glucose, CSF | 40-70 mg/dL | 2.2-3.9 mmol/L |
| Pressure, CSF | 70-180 mm H2O | 70-180 mm H2O |
| Proteins, total, CSF | <40 mg/dL | <0.40 g/L |
Hematology: complete blood count
| Test | US units | SI units |
|---|---|---|
| Hematocrit | Male: 41%-53% | Male: 0.41-0.53 |
| Female: 36%-46% | Female: 0.36-0.46 | |
| Hemoglobin, blood | Male: 13.5-17.5 g/dL | Male: 135-175 g/L |
| Female: 12.0-16.0 g/dL | Female: 120-160 g/L | |
| Mean corpuscular hemoglobin (MCH) | 25-35 pg/cell | 0.39-0.54 fmol/cell |
| Mean corpuscular hemoglobin concentration (MCHC) | 31%-36% Hb/cell | 4.8-5.6 mmol Hb/L |
| Mean corpuscular volume (MCV) | 80-100 µm³ | 80-100 fL |
| Leukocyte count (WBC) | 4500-11,000/mm³ | 4.5-11.0 × 10⁹/L |
| Neutrophils, segmented | 54%-62% | 0.54-0.62 |
| Neutrophils, bands | 3%-5% | 0.03-0.05 |
| Lymphocytes | 25%-33% | 0.25-0.33 |
| Monocytes | 3%-7% | 0.03-0.07 |
| Eosinophils | 1%-3% | 0.01-0.03 |
| Basophils | 0%-0.75% | 0.00-0.0075 |
| Platelet count | 150,000-400,000/mm³ | 150-400 × 10⁹/L |
Hematology: blood volume
| Test | US units | SI units |
|---|---|---|
| Plasma volume | Male: 25-43 mL/kg | Male: 0.025-0.043 L/kg |
| Female: 28-45 mL/kg | Female: 0.028-0.045 L/kg | |
| Red cell volume | Male: 20-36 mL/kg | Male: 0.020-0.036 L/kg |
| Female: 19-31 mL/kg | Female: 0.019-0.031 L/kg |
Hematology: coagulation
| Test | US units | SI units |
|---|---|---|
| Partial thromboplastin time, activated (aPTT) | 25-40 seconds | 25-40 seconds |
| Prothrombin time (PT) | 11-15 seconds | 11-15 seconds |
| D-dimer | ≤250 ng/mL | ≤1.4 nmol/L |
Hematology: other tests
| Test | US units | SI units |
|---|---|---|
| Reticulocyte count | 0.5%-1.5% | 0.005-0.015 |
| Erythrocyte count (RBC) | Male: 4.3-5.9 million/mm³ | Male: 4.3-5.9 × 10¹²/L |
| Female: 3.5-5.5 million/mm³ | Female: 3.5-5.5 × 10¹²/L | |
| Erythrocyte sedimentation rate (ESR, Westergren) | Male: 0-15 mm/h | Male: 0-15 mm/h |
| Female: 0-20 mm/h | Female: 0-20 mm/h | |
| CD4+ T-lymphocyte count | ≥500/mm³ | ≥0.5 × 10⁹/L |
| Hemoglobin A1c | ≤6% | ≤42 mmol/mol |
Urine
| Test | US units | SI units |
|---|---|---|
| Calcium, urine | 100-300 mg/24 h | 2.5-7.5 mmol/24 h |
| Osmolality, urine | 50-1200 mOsmol/kg H2O | 50-1200 mOsmol/kg H2O |
| Oxalate, urine | 8-40 µg/mL | 90-445 µmol/L |
| Proteins, total, urine | <150 mg/24 h | <0.15 g/24 h |
Body mass index
| Test | US units | SI units |
|---|---|---|
| Body mass index (BMI) | Adult: 19-25 kg/m² | Adult: - |
How to use this table
- Find one test. Type its name or a short form in the search box: “potassium”, “K”, “BUN”, “A1c” or “TSH” all work.
- Choose your units. The real exam shows both columns. Pick US or SI if you only want one while you study.
- Jump to a group. The buttons above the table go straight to electrolytes, liver tests, hormones, blood counts, cerebrospinal fluid, urine and the rest.
- Print it. The print button prints the full table with nothing else on the page. To keep a file, choose “Save as PDF” in your printer window.
Where these values come from
USMLE publishes the table in its free sample question booklets on usmle.org. We copied every value from the Step 1 booklet and checked each one against the Step 2 CK booklet on 14 October 2026. The two booklets list the same values.
The Step 1 booklet says questions on the real exam are presented with “use of the USMLE Laboratory Values table”. The Step 2 CK booklet describes it as a “Normal Laboratory Values” button on the exam screen.
If USMLE changes a value, we will update this page. The date at the top shows when we last checked.
NBME normal lab values on exam day
You do not need to memorise the whole sheet. The table is one click away during the exam and during NBME self-assessments, so a question can give you an unusual value without stating whether it is normal.
What costs time is opening the table for every question. Most students learn the values that come up in almost every block and look up the rest:
- Electrolytes: sodium 136-146, potassium 3.5-5.0, chloride 95-105, bicarbonate 22-28 mEq/L.
- Kidney: urea nitrogen 7-18 mg/dL, creatinine 0.6-1.2 mg/dL.
- Glucose: fasting 70-100 mg/dL.
- Blood count: hemoglobin 13.5-17.5 g/dL in men and 12.0-16.0 g/dL in women, leukocytes 4500-11,000/mm³, platelets 150,000-400,000/mm³.
- Arterial blood gas: pH 7.35-7.45, PCO2 33-45 mm Hg, PO2 75-105 mm Hg.
Values such as 17-ketosteroids or the cortisol times are rare enough to look up when they appear.
NBME lab values PDF
USMLE does not publish the table as a separate PDF. It appears on pages 7 to 9 of the Step 1 sample question booklet on usmle.org. Files shared on other sites as an “NBME lab values PDF” are often older copies, and some show ranges that differ from the official table.
The print button on this page gives you a clean copy of the current values. In the print window, choose “Save as PDF” to keep it as a file on your phone or computer.
NBME lab values for Step 2 CK and Step 3
The same table is used for Step 1, Step 2 CK and Step 3. The Step 2 CK sample booklet prints the same values as the Step 1 booklet, so there is no separate Step 2 sheet to learn.
What changes between Steps is how you use the values. Step 1 questions ask why a value is abnormal. Step 2 CK and Step 3 questions ask what to do next because of it.
NBME reference values in SI units
SI units are used in most countries outside the US, so many international graduates first learned their lab values in SI. The SI column gives the same ranges in the units you may know better. Choose “SI” in the units switch above the table to see only that column.
Two values look different from what many students expect:
- Hemoglobin is 135-175 g/L in SI, the same range as 13.5-17.5 g/dL.
- Creatinine is 53-106 µmol/L in SI, the same range as 0.6-1.2 mg/dL.
Practise with the values
Lab values stick when you use them in questions. Our USMLE Step 1 recalls and USMLE Step 2 CK recalls are written by our own authors in the exam’s format, with lab values given the way the real exam gives them.
After a practice test, our NBME score calculator shows what your result predicts.
Questions people ask
Can I see lab values during the USMLE?
Yes. The USMLE sample question booklets say questions are presented with the Laboratory Values table available on screen.
Are NBME lab values the same as USMLE lab values?
Yes. NBME writes the USMLE exams, and NBME practice tests use the same table.
Are the lab values different for Step 2 CK?
No. The Step 1 and Step 2 CK sample booklets print the same values.
Why do some lab values sheets show different numbers?
Many sheets online are copied from older tables or from hospital ranges. Hospital ranges differ from one lab to another. For the exam, only the USMLE table counts.
Should I memorise all the lab values?
Learn the common ones listed above, so you do not open the table for every question. Look up the rare ones when they appear.
Sources
Opened on 14 October 2026:
- USMLE, Step 1 sample test questions (Laboratory Values on pages 7-9): https://www.usmle.org/exam-resources/step-1-materials/step-1-sample-test-questions
- USMLE, Step 2 CK sample test questions: https://www.usmle.org/exam-resources/step-2-ck-materials/step-2-ck-sample-test-questions