Everything You Need to Know About a Complete Blood Count


A complete blood count can help detect a variety of disorders, including infections, anemia, diseases of the immune system and blood cancers. A complete blood count is used to look at overall health.

Here are a few of the key results from a complete blood count.

Cholesterol: Lipids are found in your blood and are stored in the tissues.

High Density Lipoprotein (HDL): This is known as “good” cholesterol. Higher levels are associated with a lower risk of heart disease. The normal range for HDL for healthy adults is 40-79 mg/dl.

Low Density Lipoprotein (LDL): This is known as the “bad” cholesterol. High levels of LDL are bad and are associated with a higher risk of heart disease and stroke. The normal range for healthy adults is less than 100 mg/dl.

Triglycerides are the main form of fat in foods and in the human body.

Blood Sugar/Glucose: A blood glucose test measures the amount of a type of sugar (glucose) in your blood. Glucose is your blood sugar.

If your blood sugar is too high, it may mean you have diabetes. Normal fasting glucose level is less than 100 mg/dL. A glucose level above 125 mg/dL can indicate diabetes.

A1C reveals your average blood glucose level over the past 3 months and can be used to monitor your diabetic control.

Anemia: Both hemoglobin and hematocrit are measured to check for anemia.

Hemoglobin is the part of the red blood cell that carries oxygen to the cells of the body. A normal hemoglobin level for a healthy adult is 12-15 g/dL. Three times the hemoglobin level equals the hematocrit.

Hematocrit is a blood test that measure the number and size of red blood cells. Hematocrit gives a percentage of red blood cells found in whole blood. Hematocrit is used to check for anemia.

Kidney Function: Your kidneys remove toxins and waste from the blood. A complete blood count will check the function of your kidneys.

Creatinine: Creatinine is a waste product in the blood created by the normal metabolism of muscle cells. When the kidneys are not working well, creatinine builds up in the blood. Healthy kidneys take creatinine in the blood and remove it through the urine.

A creatinine level of 1.2 for women and more than 1.4 for men may be an early sign that the kidneys are not working properly.

Blood urea nitrogen: BUN test reveals important information about how well your kidneys are working. A BUN test measures the amount of urea nitrogen in the blood and how quickly waste is being removed.

Urea nitrogen is a waste product made when your liver breaks down protein. Healthy kidneys filter urea and remove other waste products from your blood. The filtered waste products leave your body through urine. If the kidneys are not working well, the urea nitrogen will stay in the blood. Higher than normal blood urea nitrogen (BUN) levels may be a sign that your kidneys are not working well.

Normal blood contains 7-20 mg of urea. If your BUN is greater than 20 mg, your kidneys may not be working at full strength.

Glomerular Filtration Rate (GFR): GFR is a blood test used to check how well the kidneys filter blood. When you have a routine blood test, GFR is often part of the basic metabolic panel. Healthcare providers use GFR to watch for the onset of kidney disease.

GFR measures how much blood passes through the glomeruli every minute. Glomeruli are the tiny filters in the kidneys that filter waste from the blood. When you have kidney disease, the glomeruli filter less blood. As a result, dangerous toxins build up in your blood. A low GFR means your kidneys are not filtering your blood as well as they should.

Monitoring your GFR is important if you’re at risk for kidney disease. In adults, the normal GFR # is usually more than 90. The normal range of kidney GFR is 100 to 130 mL in men, and 90 to 120 mL in women below 40.

GFR of 60-89 may mean early-stage kidney disease; GFR of 15-59 may mean kidney disease; and GFR below 15 may mean kidney failure. Your provider may diagnose chronic kidney disease when your GFR stays below 60 mL for 3 months in a row. Generally, the higher the number, the better your kidneys will function. A GFR higher than 60 means you have at least 60% kidney function.

According to the National Kidney Foundation, normal results range from 90 to 20 milliliters. Older people will have lower than normal GFR levels because GFR decreases with age. The average GFR for someone in their 20’s is about 116 mL and it drops to 85 mL for people in their 60’s.

Liver Function: Liver function tests are blood tests to help diagnose and monitor liver disease or damage. Liver function tests are blood tests that measure different substances produced by the liver. Elevated AST and ALT levels may indicate liver injury.

ALT (alanine transaminase) and AST (aspartate transaminase) are enzymes found mostly in the liver that is released into the bloodstream after acute liver cell damage. On average, normal ranges are: ALT: 0 to 45 iv/l; AST: 0 to 35 iv/l.

Blood Clotting: International Normalized Ratio (INR) measures how long it takes for blood to clot. Blood clotting needs vitamin K and a protein that is made by the liver.