How to Understand Your Lab Results?

What is a laboratory test?
A laboratory (lab) test checks a sample of your blood, urine (pee), or other body fluid or tissue to learn about your health. The sample is sent to a lab where health care professionals test it to see if it contains certain substances and, if so, how much.

Some lab tests can clearly show whether you do or don't have a specific health condition. For example, a pregnancy test can show whether or not a person is pregnant.

Other lab tests provide more general information about your health and possible problems. Test results that aren't normal give your health care provider clues about the type of health problems you may have. The results help your provider decide whether you need more tests and which ones will be most useful for diagnosing or ruling out certain conditions.

Lab tests are an important part of your health care. But they don't provide a complete picture of your health. Even though you may get your test results in your electronic health record (EHR), it's still important to talk with your provider to find out what your results really mean for you.

To get a full picture of your health, your provider will use your test results along with information from your physical exam, health history, family health history, and sometimes imaging tests, such as x-rays. In most cases, combining that information leads to a more accurate diagnosis than the results from any one lab test.

Why do I need a lab test?

Lab tests are used in different ways, including to help:

Diagnose or rule out a specific disease or condition. Tests to diagnose health problems are done when you have signs or symptoms of a certain disease or condition. Sometimes more than one test is needed to confirm a diagnosis.

A strep A test is an example of a diagnostic test. If you're sick with a bad sore throat and other symptoms, this test can show you whether you're infected with the bacteria that causes strep throat.

Monitor a disease and/or treatment. If you've already been diagnosed with a disease, you may need lab tests to see if your condition is getting better, worse, or staying the same. Tests can also show if your treatment is working.

A blood glucose test is an example of a monitoring test. It's used to monitor diabetes and diabetes treatment. It may also be used to diagnose the disease.

Plan your treatment. Certain tests can help show which treatments are likely to be most effective for a specific disease.

Tumor marker tests are an example of testing to find out which treatments are likely to work to fight certain types of cancer.

What is a reference range?

Lab test results are reported in different ways. Some results are a number. But how do you know what that number means?

To answer that question, your lab report tells you whether your test result is in a normal range called a reference range or "normal values."

common for healthy people to sometimes have results outside the reference range. And people with health problems can have results in the normal range, too.

What can affect my results?

The accuracy of certain test results may be affected by what you eat, medicines you take, and even how your feel when you provide your test sample. Common things that affect tests include:

• Eating and drinking certain foods and drinks
• Taking certain medicines or supplements
• Exercising hard before your test
• Having a menstrual period at the time of your tested

Your provider will let you know if you need to prepare for your test. Follow your provider's instructions carefully. That will help make sure your test results are as accurate as possible. Before your test, let your provider know about all the prescription and over-the-counter medicines you take as well as vitamins and other supplements.

What if I do a home test?

At-home test kits are available for many types of lab tests. The kits provide everything you need to collect a sample of body fluid or cells to send to a lab. At-home tests should never replace testing that your provider orders. Ask your provider or pharmacist to recommend a test you can trust. And talk with your provider about your results, even if they're normal.

Lab Test Normal Value 

Electrolytes:

•    Ammonia: 15-50 µmol/L
•    Ceruloplasmin: 15-60 mg/dL
•    Chloride: 95-105 mmol/L
•    Copper: 70-150 µg/dL
•    Creatinine: 0.8-1.3 mg/dL
•    Blood urea nitrogen: 8-21 mg/dL
•    Ferritin: 12-300 ng/mL (men), 12-150 ng/mL (women)
•    Glucose: 65-110 mg/dL
•    Inorganic phosphorous: 1-1.5 mmol/L
•    Ionized calcium: 1.03-1.23 mmol/L
•    Magnesium: 1.5-2 mEq/L
•    Phosphate: 0.8-1.5 mmol/L
•    Potassium: 3.5-5 mmol/L
•    Pyruvate: 300-900 µg/dL
•    Sodium: 135-145 mmol/L
•    Total calcium: 2-2.6 mmol/L (8.5-10.2 mg/dL)
•    Total iron-binding capacity: 45-85 µmol/L
•    Total serum iron: 65-180 µg/dL (men), 30-170 µg/dL (women)
•    Transferrin: 200-350 mg/dL
•    Urea: 1.2-3 mmol/L
•    Uric acid: 0.18-0.48 mmol/L
•    Zinc: 70-100 µmol/L

Hematology

•    Hemoglobin: 13-17 g/dL (men), 12-15 g/dL (women)
•    Hematocrit 40%-52% (men), 36%-47%
•    Glycosylated hemoglobin 4%-6%
•    Mean corpuscular volume (MCV): 80-100 fL
•    Red blood cell distribution width (RDW): 11.5%-14.5%
•    Mean corpuscular hemoglobin (MCH): 0.4-0.5 fmol/cell
•    Mean corpuscular hemoglobin concentration (MCHC): 30-35 g/dL
•    Reticulocytes 0.5%-1.5%
•    White blood cells (WBC) 4-10 x 10^9/L
•    Neutrophils: 2-8 x 10^9/L
•    Bands: < 1 x 10^9/L
•    Lymphocytes: 1-4 x 10^9/L
•    Monocytes: 0.2-0.8 x 10^9/L
•    Eosinophils: < 0.5 x 10^9/L
•    Platelets: 150-400 x 10^9/L
•    Prothrombin time: 11-14 sec
•    International normalized ratio (INR): 0.9-1.2
•    Activated partial thromboplastin time (aPTT): 20-40 sec
•    Fibrinogen: 1.8-4 g/L
•    Bleeding time: 2-9 min

Lipid Profile:

•    Triglycerides: 50-150 mg/dL
•    Total cholesterol: 3-5.5 mmol/L
•    High-density lipoprotein (HDL): 40-80 mg/dL
•    Low-density lipoprotein (LDL): 85-125 mg/dL

Liver Profile:
 
Standard range blood test results for typical liver function tests include:

ALT. 7 to 55 units per liter (U/L).
AST. 8 to 48 U/L.
ALP. 40 to 129 U/L.
Albumin. 3.5 to 5.0 grams per deciliter (g/dL).
Total protein. 6.3 to 7.9 g/dL.
Bilirubin. 0.1 to 1.2 milligrams per deciliter (mg/dL).
GGT. 8 to 61 U/L.
LD. 122 to 222 U/L.
PT. 9.4 to 12.5 second
Total protein
Bilirubin. 0.1 to 1.2 milligrams per deciliter (mg/dL).
GGT . 8 to 61 U/L .
LD . 122 to 222 U/L .

Acid base:

•    pH: 7.35-7.45
•    Base excess: (-3)-(+3)
•    H+: 36-44 nmol/L
•    Partial pressure of oxygen (pO2): 75-100 mm Hg
•    Oxygen saturation: 96%-100%
•    Partial pressure of carbon dioxide (pCO2): 35-45 mm Hg
•    Bicarbonate (HCO3): 18-22 mmol/L

Gastrointestinal function:

•    Albumin: 35-50 g/L
•    Alkaline phosphatase: 50-100 U/L
•    Alanine aminotransferase (ALT): 5-30 U/L
•    Amylase: 30-125 U/L
•    Aspartate aminotransferase (AST): 5-30 U/L
•    Direct bilirubin: 0-6 µmol/L
•    Gamma glutamyl transferase: 6-50 U/L
•    Lipase: 10-150 U/L
•    Total bilirubin: 2-20 µmol/L
•    Total protein: 60-80 g/L

Cardiac enzymes:

See the list below:
•    Creatine kinase: 25-200 U/L
•    Creatine kinase MB (CKMB): 0-4 ng/mL
•    Troponin: 0-0.4 ng/mL

Hormones:

See the list below:
•    17 hydroxyprogesterone (female, follicular): 0.2-1 mg/L
•    Adrenocorticotropic hormone (ACTH): 4.5-20 pmol/L
•    Estradiol: 1.5-5 ng/dL (male), 2-14 ng/dL (female, follicular), 2-16 ng/dL (female, luteal), < 3.5 ng/dL (postmenopausal)
•    Free T3: 0.2-0.5 ng/dL
•    Free T4: 10-20 pmol/L
•    Follicle-stimulating hormone (FSH): 1-10 IU/L (male), 1-10 IU/L (female, follicular/luteal), 5-25 IU/L (female, ovulation), 30-110 IU/L (postmenopause)
•    Growth hormone (fasting) : 0-5 ng/mL
•    Progesterone: 70-280 (ovulation), ng/dL
•    Prolactin: < 14 ng/mL
•    Testosterone (male): 10-25 nmol/L
•    Thyroxine-binding globulin: 12-30 mg/L
•    Thyroid-stimulating hormone (TSH): 0.5-5 mIU/L
•    Total T4, adult: 4.9-11.7 mg/dL
•    Total T3: 0.7-1.5 ng/dL
•    Free T3: 1.7-3.7 pg/mL

Vitamins:

•    Folate (serum) : 7-36 nmol/L
•    Vitamin A: 30-65 µg/dL
•    Vitamin B12: 130-700 ng/L
•    Vitamin C: 0.4-1.5 mg/dL
•    Vitamin D: 5-75 ng/mL

Tumor markers:

•    Alpha fetoprotein: 0-44 ng/mL
•    Beta human chorionic gonadotropin (HCG): < 5 IU/I
•    CA19.9: < 40 U/mL
•    Carcinoembryonic antigen (CEA): < 4 ug/L
•    Prostatic acid phosphatase (PAP): 0-3 U/dL
•    Prostate-specific antigen (PSA): < 4 ug/L

Miscellaneous/ Extras:

•    Alpha 1-antitrypsin: 20-50 µmol/L
•    Angiotensin-converting enzyme: 23-57 U/L
•    C-reactive protein: < 5 mg/L
•    D-dimer: < 500 ng/mL
•    Erythrocyte sedimentation rate (ESR): Less than age/2 mm/hour
•    Lactate dehydrogenase (LDH): 50-150 U/L
•    Lead: < 40 µg/dL
•    Rheumatoid factor: < 25 IU/ml