Common Laboratory Reference Intervals
Laboratory Test
*Activated partial thromboplastin time
(aPTT)
Conventional Units (SI Units)
30-40 sec (30-40 sec)
For those receiving anticoagulant therapy, aPTT is 1.5–2.5
times control value in seconds.
Alanine aminotransferase (ALT;
formerly known as serum glutamate
pyruvate transferase [SGPT])
4-36 U/L (4-36 U/L)
Albumin
3.5-5.0 g/dL (35-50 g/L)
Ammonia
10–80 mcg/dL (6–47 mcmol/L)
Amylase
Aspartate aminotransferase (AST)
(formerly known as serum glutamic
oxaloacetic transferase [SGOT])
60–120 Somogyi units/dL (100–300 U/L)
Bilirubin
0-35 U/L (0-35 U/L)
Total: 0.3 - 1.0 mg/dL (5.1 - 17 mcmol/L)
Indirect: 0.2 - 0.8 mg/dL (3.4 - 12 mcmol/L)
Direct: 0.1 - 0.3 mg/dL (1.7 - 5.1 mcmol/L)
Blood culture
No growth
Bacteremia: Bacteria growing in the blood can often be
grown in the culture medium in the microbiology laboratory.
When bacteremia is suspected, antibiotics should be started
immediately after blood cultures are obtained.
*Blood gases – arterial and venous
values
Arterial pH 7.35-7.45 (7.35-7.45)
Venous pH 7.31-7.41 (7.31-7.41)
PaCO2 35-45 mm Hg (35-45 mm Hg)
Arterial PaO2 80-100 mm Hg (80-100 mm Hg)
Venous PvO2 40-50 mm Hg (40-50 mm Hg)
Bicarbonate 21-28 mEq/L (21-28 mmol/L)
*Blood urea nitrogen (BUN)
10 - 20 mg/dL (3.6 - 7.1 mmol/L)
Calcium
9-10.5 mg/dL (2.25-2.75 mmol/L)
Cerebrospinal fluid (CSF)
Lumbar Protein: 15-45 mg/dL (0.15-0.45 g/L)
Glucose: 50-75 mg/dL (2.8-4.2 mmol/L)
WBCs (white blood cells): 0-5 cells/mcL (0-5 × 106/L)
RBCs (red blood cells): negative (negative)
Chloride: 116–122 mEq/L of CSF (116–122 mmol/L of CSF)
Pressure: <20 cm H2O (<20 cm H2O)
Chloride
98-106 mEq/L (98-106 mmol/L)
*Cholesterol
<200 mg/dL (<5 mmol/L) age dependent
Note: see below for low density lipoprotein (LDL), high
density lipoprotein (HDL), and triglyceride levels
Creatine kinase (CK)
Male: 55-170 U/L (55-170 U/L)
Female: 30-135 U/L (30-135 U/L)
Creatine kinase isozyme of heart
male: 2 -6 ng/mL (2 - 6 mcg/L)
CK-MB (CK-2)
female: 2 - 5 ng/mL (2 - 5 mcg/L)
*Creatinine
male, 0.6-1.2 mg/dL (53-106 mcmol/L)
female 0.5-1.1 mg/dL (44-97 mcmol/L)
D-dimer
<50 ng/mL (<3.0 mmol/L)
Erythrocyte sedimentation rate (ESR),
Westergren
Male: ≤15 mm/hr (≤15 mm/hr)
Female: ≤20 mm/hr (≤20 mm/hr)
Ferritin (serum)
Male: 12-300 ng/mL (12-300 ng/L)
Female: 10-150 ng/mL (10-150 ng/L)
Fibrinogen
60-100 mg/dL (2.0–5.0 g/L)
*Glucose, fasting
70-99 mg/dL (3.9-5.5 mmol/L)
Glomerular filtration rate (GFR)
>60 mL/min/1.73 m2 (age dependent)
High density lipoprotein (HDL)
>60 mg/dL (>1.55 mmol/L)
*Hematocrit (altitude dependent)
Male: 42-52% (0.42-0.52 volume fraction)
Female: 37-47% (0.37-0.47 volume fraction)
*Hemoglobin (altitude dependent)
Male: 14-18 g/dL (140-180 mmol/L)
Female: 12-16 g/dL (120-160 mmol/L)
*Hemoglobin, glycosylated or glycated
(HbA1c [A1c])
<6% (adult without diabetes)
Homocysteine (dependent on gender
and age)
4.5 -11.9 mcmol/L (4.5 -11.9 mcmol/L)
*International normalized ratio (INR)
0.81-1.2 (0.81-1.2)
Lactic acid (venous)
5–20 mg/dL (0.6–2.2 mmol/L)
Low density lipoprotein (LDL)
<100 mg/dL (<2.59 mmol/L)
Lipase
0 – 160 U/L (0 – 160 U/L)
Magnesium
1.8–2.6 mEq/L (0.74–1.07 mmol/L)
Myoglobin
<90 ng/mL (1.0–5.3 nmol/L)
B-type natriuretic peptide
<100 ng/mL (<100 mcg/L)
Arterial: 95%-100% (95%-100%)
Venous: 60%-80% (60%-80%)
Oxygen Saturation
Phosphatase alkaline (ALP)
38-126 U/L (0.65-2.14 µkat/L)
Phosphorus, phosphate
3.0-4.5 mg/dL (0.97-1.45 mmol/L)
*Platelets
150,000-400,000/mm3 (150-400 × 109/L)
*Potassium
3.5-5.0 mEq/L (3.5-5.0 mmol/L)
Protein Total
6.4-8.3 g/dL (64-83 g/dL)
Prothrombin time (Protime, PT)
11-12.5 sec (11-12.5 sec)
For those receiving anticoagulant therapy, PT is 1.5–2.0
times control value in seconds.
Red blood cells
Male: 4.7–6.2 × 1012/L (4.7–6.2 × 1012/L)
Female: 4.2–5.4 × 1012/L (4.2–5.4 × 1012/L)
*Sodium
135-145 mEq/L (135-145 mmol/L)
Specific gravity urine, Random
1.003-1.030 (same as conventional units)
Thyroid stimulating hormone (TSH)
2–10 mcIU/mL (2–10 Miu/L)
Thyroxine (T4), total
5–12 mcg/dL (64–154 nmol/L)
Thyroxine (T4), free
Triglycerides
0.8–2.8 ng/dL (10–36 pmol/L)
Female:35-135 mg/dL (0.40-1.52 mmol/L)
Male: 40-160 mg/dL (0.45-1.81 mmol/L)
Troponin
Uric acid
A troponin value of 0.05 to 0.49 ng/mL is considered
indeterminate; a value greater than 0.50 ng/mL indicates a
strong probability of acute myocardial infarction.
Male: 4.0-8.5 mg/dL (240-501 mcmol/L)
Female: 2.7-7.3 mg/dL (160-430 mcmol/L)
Urine
bilirubin, glucose, hemoglobin negative
Ph 4.0-8.0
protein 0-trace
specific gravity 1.003-1.030
Vitamin D (Total 25-hydroxyvitamin D)
30–80 ng/mL (75–200 nmol/L)
*White blood cell (WBC) count
5000-10,000/mm3 (5-10 × 109/L)
Segmented Neutrophils
62-68% (2.5-7.5 × 109/L)
Band Neutrophils
0-9% (0-1 × 109/L)
Lymphocytes
1000-4000/mm3 - 20-40% (0.1-0.4 × 109/L)
Monocytes
100-700/mm3 - 2-8% (0.1-0.7 × 109/L)
Eosinophils
50-100/mm3 - 1-4% (0.00-0.5 × 109/L)
Basophils
15-50/mm3 - 0.5-1% (0.02-0.05 × 109/L)
Note: Laboratory values may vary with different techniques and in different laboratories.
Note: In the table, *Indicates the need to know laboratory values as specified in: NCLEX-RN®
Examination: Test Plan for the National Council Licensure Examination for Registered Nurses (Effective
April 2019), Chicago: National Council of State Boards of Nursing, Inc. (NCSBN).
References:
Ignatavicius, D., Workman, M., Rebar, C., Heimgartner, N. (2021). Concepts for interprofessional
collaborative care (10th ed.). St. Louis, MO: Saunders.
Lewis et.al (2019), Medical-Surgical Nursing in Canada: Assessment and Management of clinical
problems (10th ed.), St. Louis: Elsevier. Appendix B Laboratory Values, Adapted by Jana Lok.
Lewis et.al (2017), Medical-Surgical Nursing: Assessment and Management of clinical problems (10th
ed.), St. Louis: Elsevier. Appendix C Laboratory Reference Intervals.
National Council of State Boards of Nursing (2018), NCLEX-RN® Examination: Test Plan for the National
Council Licensure Examination for Registered Nurses (Effective April 2019), Chicago: National Council
of State Boards of Nursing, Inc. (NCSBN).
Pagana, K., Pagana, T., Pike-MacDonald, S. (2019) Mosby’s Canadian manual of diagnostic and
laboratory tests, (2nd Canadian ed.) St. Louis: Elsevier (Canadian Editor, Sandra A. Pike-MacDonald).
Copyright © 2020, 2019 by Saunders, an imprint of Elsevier Inc.