Decoding Blood Tests: A GoodRx Guide to Lab Results - GoodRx (2024)

It is normal to feel a little anxious when you get the results of a blood test. And the anxiety can build when you look at the results and can’t figure out what they mean or if your results are “normal.” You’re not alone. Most lab results look like they’re in a different language. And it doesn’t help that most people get their results before they can talk to their provider about them.

We’re here to walk you through the most common lab tests and what they mean. We’ll also explain which values are considered normal. But keep in mind that every lab is a little different. This means the normal ranges — and the way they are measured and reported — can vary. Most blood test results come with the range that is considered normal for that lab.

Complete blood count (CBC)

A CBC measures the different types of cells in the blood. It’s one of the most common blood tests and is usually a part of routine lab work. It can also be helpful in diagnosing things like infections, blood diseases, and immune system disorders.

The numbers on a CBC that providers usually pay most attention to include:

• WBC (white blood cells): These blood cells help fight infection. A normal range is 4,500 to 11,000 cells per mL.

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• RBC (red blood cells): These blood cells carry oxygen throughout the body. A normal range is 4.1 to 5.9 million per mL.

• HGB (hemoglobin): This protein helps red blood cells carry oxygen. A normal range is 12.3 to 17.5 grams per dL.

• PLT (platelets): This is a small molecule that helps with clotting. A normal range is 150,000 to 400,000 cells per mL.

A CBC also includes severals tests that measure more details about your red blood cells:

• HCT (hematocrit): This is the percentage of your blood that is made up of red blood cells. A normal range is 35.9% to 50.4%.

• MCV (mean corpuscular volume): This is the average size of your red blood cells. A normal range is 80 fL to 96 fL.

• MCH (mean corpuscular hemoglobin): This is the average amount of hemoglobin in each red blood cell. A normal range is 27.5 pg to 33.2 pg (picograms).

• MCHC (mean corpuscular hemoglobin concentration): This is the average concentration of hemoglobin in blood. A normal range is 33.4 to 35.5 grams per dL.

• MPV (mean platelet volume): This is the average size of your platelets. A normal range is 7 fL to 10 fL.

Some CBCs come with a “diff,” which stands for differential. It’s a way to break down the different types white blood cells in the blood. Each one is measured by a percentage:

• Neut (neutrophils): These white blood cells fight infection. A normal range is 1,800 to 7,800 cells per mL.

• Lymph (lymphocytes): These white blood cells learn how to recognize different infections. A normal range is 1,000 to 4,800 cells per mL.

• Mono (monocytes): These cells remove damaged tissue. A normal range is 0 to 800 cells per mL.

• Eos (eosinophils): This type of white blood cell fights parasites. It also responds to allergens. A normal range is 0 to 450 cells per mL.

• Baso (basophils): These cells play a part in allergic reactions by releasing histamine. A normal range is 0 to 200 cells per mL.

Electrolyte panel

An electrolyte panel, or basic metabolic panel (BMP), measures several different substances in the blood. Along with the CBC, it’s usually a part of a routine checkup because it gives a glimpse of your overall health.

Healthcare providers can use an electrolyte panel to assess things like hydration and nutrition status. It also measures kidney function and the acid-base balance in the blood.

An electrolyte panel reports:

• Na (sodium): This is the amount of salt in the blood. Sodium helps with fluid balance. A normal range is 134 mmol/L to 144 mmol/L.

• K (potassium): This electrolyte helps the heart beat regularly. The nerves and muscles also need potassium to properly function. A normal range is 3.5 mmol/L to 5.2 mmol/L.

• Cl (chloride): This electrolyte helps with fluid balance. A normal range 96 mmol/L to 106 mmol/L.

• CO2 (carbon dioxide): This helps measure the acid-base balance in the blood. A normal range is 20 mmol/L to 29 mmol/L.

• BUN (blood urea nitrogen): This substance builds up in the blood when the kidneys are not working normally. So it helps measure kidney function. A normal range is 9 mg/dL to 23 mg/dL.

• Cr (creatinine): This substance also increases when the kidneys are not working right. A normal range is 0.57 mg/dL to 1 mg/dL.

• Glucose (blood sugar): This measures your blood sugar. A normal range is 65 mg/dL to 99 mg/dL.

You may also see your electrolyte panel reported as a complete metabolic panel (CMP) rather than a BMP. This just means it measures all of the electrolytes above, plus liver function tests.

Blood glucose

A blood glucose test measures the amount of sugar in the blood. It is a standard part of the electrolyte panel above. But it can also be measured separately with a finger prick.

Your blood sugar will vary depending on when you last ate. A normal range for a fasting blood sugar (meaning you have not eaten for 8 hours) is 65 mg/dL to 99 mg/dL. A normal range for a random blood sugar is 65 mg/fL to 199 mg/fL.

HbA1c

Hemoglobin A1C (HbA1c or A1C) is a blood test that measures your average blood sugar over the past 2 to 3 months. So it’s a useful test to figure out if you’re at risk for diabetes. And if you have diabetes, it can help figure out if you need new or different medications to keep your blood sugar in check. A normal level is below 5.7%

Liver function tests (LFTs)

Liver function tests measure enzymes and proteins in the blood that the liver controls. Other names for these tests are “liver enzymes” or “liver panel.” They help evaluate how well the liver is working. They can also help diagnose things like liver inflammation, liver damage, or even blockages and gallstones.

LFTs include:

• ALT (alanine aminotransferase): This enzyme can increase when there is inflammation in the liver. A normal range is 0 IU/L to 32 IU/L.

• AST (aspartate transaminase): Similar to ALT, this enzyme increases when there is liver inflammation of any kind. A normal range is 0 IU/L to 40 IU/L.

• ALP (alkaline phosphatase): This enzyme is released into the blood by both bone and liver. So a higher than normal value can be a sign of liver and/or bone problems. A normal range is 39 IU/L to 117 IU/L.

• Albumin: This protein is in the blood and can be affected by many things. It can also be a sign of kidney or liver conditions. A normal range is 3.8 g/dL to 4.8 g/dL.

• TP (total protein): This can go up or down with changes in liver function. It can also change with other conditions or nutritional status. A normal range is 6 g/dL to 8.5 g/dL.

• Bilirubin: This pigment is released when old red blood cells break down. Bilirubin can help evaluate liver function because it is the liver’s job to get rid of it. A high bilirubin level can have many different causes and does not always mean there’s a liver problem. A normal range is 0 mg/dL to 1.2 mg/dL.

• GGT (gamma-glutamyltransferase): This is an enzyme found in blood that may be a sign of liver injury. A normal range is 6 IU/L to 50 IU/L.

• LDH (lactate dehydrogenase): This is another enzyme that is found in the liver. Abnormal values can mean liver disease or a number of other conditions — including infection, muscle injury, and cancers. A normal range is 50 IU/L to 150 IU/L.

Thyroid function tests (TFTs)

Thyroid function tests measure how much thyroid hormone is in the blood. This can help figure out if someone has an underactive or overactive thyroid. The main thyroid test is:

• TSH (thyroid-stimulating hormone): This hormone tells the thyroid to produce thyroid hormone. When it is high, it means the thyroid is not making enough thyroid hormone. When it is low, it can mean the thyroid is overactive and making too much thyroid hormone. A normal range is 0.4 mIU/mL to 4 mIU/mL.

If your TSH is abnormal, then your provider may also check:

• Free T4: The thyroid makes this hormone. It helps regulate energy, mood, and body temperature. A high number might mean an overactive thyroid. A normal range is 0.8 ng/dL to 2 ng/dL.

• Free T3: The thyroid also makes this hormone. It helps regulate metabolism. Similar to T4, a high number might mean an overactive thyroid. A normal range is 1.5 pg/mL to 6 pg/mL.

Cholesterol tests

Cholesterol tests measure the amount of several different types of cholesterol in the blood. Other names are “lipid profile” or “lipid panel.” These tests include:

• LDL (low-density lipoprotein): This is sometimes called the “bad” cholesterol because a high level can increase your risk of heart disease. A normal level is less than 100 mg/dL.

• HDL (high-density lipoprotein): This is considered “good” cholesterol because a higher level can decrease your risk of heart disease. A normal level is greater than 60 mg/dL.

• Triglycerides (TGs): This is a type of cholesterol that the body uses for energy. But a high level can also increase risk of heart disease. A normal level is less than 150 mg/dL.

• Total cholesterol: This is the total of the above three numbers (LDL, HDL, and triglycerides). A normal level is less than 200 mg/dL.

Troponin

Troponins are proteins found in heart muscle. They are also called “cardiac enzymes.” They are released into the blood whenever the heart is strained, like during a heart attack. But it can also happen without heart disease, like when someone has a high heart rate for some other reason.

There are two different types of troponin:

• Troponin I: A normal level is less than 0.03 ng/mL.

• Troponin T: A normal level is less than 0.1 ng/mL.

D-dimer

A D-dimer test can measure how the blood is clotting. Providers use it along with other tests to help figure out if someone is at risk for a blood clot.

The higher the number, the higher your risk for a blood clot. But an abnormal result does not necessarily mean you have a blood clot. And many conditions — from age to pregnancy — naturally increase the D-dimer level.

D-dimer tests are not standardized, so each lab may do the test differently. This means normal ranges are specific to the lab where you do the test.

INR

The INR (international normalized ratio) is another blood test that looks at how well the blood is clotting. You may see this reported as “PT/INR.” This is because the INR is calculated based on a PT test (prothrombin time), which measures how long it takes for the blood to clot.

INR is mostly used for people who take blood thinners — particularly warfarin (Coumadin). In those cases, providers use the INR to make sure you are getting the right dose of your blood thinner. The higher the INR, the “thinner” the blood.

A normal range for PT is 10.9 to 12.5 seconds.

A normal INR — for someone who is not taking a blood thinner — is around 1. For people who take warfarin, the target INR is usually between 2 and 3.

ESR and CRP

ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein) are blood tests that measure inflammation in the body. They measure general inflammation, so they’re not specific to any one condition. For example, it can be a sign of infection or autoimmune disease.

A normal level for ESR is less than 20 mm/hr.

A normal level for CRP is less than 1 mg/dL.

Urinalysis (UA)

A urinalysis (UA) is a test that checks for many different substances in the urine. This can help diagnose anything from urinary tract infections (UTIs) to kidney dysfunction. A typical UA includes:

• Specific gravity: This is a measure of how concentrated the urine is. This can help figure out your hydration status. A normal range is 1.005 to 1.030.

• Urinary pH: This measures how acidic the urine is. This can help figure out the acid-base balance in the body. A normal range is 4.5 to 8.

• Glucose: When someone has a high blood sugar, some of that sugar will go into the urine. A normal value is 0.

• Ketones: Ketones are produced in the body when there is abnormal fat breakdown. A normal value is 0.

• Protein: Many conditions that put stress on the body can cause protein in the urine. Examples include strenuous exercise, dehydration, and pregnancy. A normal value is 0, or a very small amount.

• Leukocyte esterase: This enzyme is released from white blood cells and can be a sign of a UTI. A normal value is 0.

• Nitrites: This is a substance produced by bacteria, so it can also be a sign of a UTI. A normal value is 0.

• Bilirubin: Bilirubin can be measured in the blood and in the urine. It’s a pigment made when red blood cells break down. A normal value is 0.

• Blood: Many times, you can’t see blood in the urine with the naked eye. This test can detect even a tiny amount of blood in the urine. A normal value is 0.

Urine drug screen (UDS)

A urine drug screen (UDS) tests for specific medications and drugs that can show up in the urine. This includes prescription medications as well as illegal substances. A urine drug test usually screens for:

• THC (tetrahydrocannabinol): This is the active compound in cannabis or marijuana.

• Opioids: This is the active ingredient of prescription medications like oxycodone or morphine. It can also be found in illegal substances like heroin.

• Amphetamines: These can include prescribed medications, such as Adderall, as well as illegal drugs such as methamphetamine.

• Benzodiazepines: This is a group of medications used to treat conditions like anxiety or seizure. Examples include alprazolam (Xanax) and diazepam (Valium).

• PCP (phencyclidine)

• Cocaine

These tests will result as “positive” when the substance is present and “negative” when it is not present.

How to read and understand your lab results

We hope this guide will help you understand your blood and urine tests. We have listed the normal ranges for most people. Keep in mind: There is natural variation depending on age and sex for some of these values. And certain medical conditions can also affect what’s normal for you.

The results often have to be interpreted as a group, rather than as individual results. And many times, the actual number is less important than the trend. If your labs are checked at regular intervals, comparing them from year to year or month to month can be more important. Your healthcare provider will be your best resource to understand what your results mean for you.