How Is A Cbc Done
If the CBC is the only blood test youâre having, you can eat and drink like you usually would.
Your part of the test is simple and takes just a few minutes. A nurse or lab tech will take a sample of blood by putting a needle into a vein in your arm. Afterward, you can leave and get back to your routine. Theyâll send the blood to a lab for review.
What Does It Mean If Your Hematocrit Is Low
Suspected anemia is the most common reason for hematocrit testing. Your healthcare provider is your best resource for information about your test result. Other conditions include:
- Blood loss due to injury or illness: Blood loss affects the number red blood cells. Fewer red blood cells mean lower hematocrit levels.
- Leukemia: You have fewer red blood cells than normal because leukemia cells in your bone marrow are displacing healthy red blood cells.
- Hemolytic anemia: Your red blood cells are breaking down or dying faster than your body can replace them.
- Hyponatremia: This condition means you have too much water in your body, which literally causes your blood to be watered down.
- Kidney disease: Low hematocrit levels are a sign of anemia. Anemia is a common complication of kidney disease.
- Thyroid disease: Thyroid hormones support red blood cell production. Fewer red blood cells mean lower hematocrit levels.
What hematocrit level is considered anemic?
If your hematocrit level is below the normal range for your sex, your provider may do more tests to check on your red blood cell levels. Anemia happens when you dont have enough red blood cells.
What Are Normal Hemoglobin Values
Normal hemoglobin values are related to the person’s age and sex. Normal values may vary slightly between test systems, and which groups of doctors have determined “normal values” for their group of patients however, the value ranges are close for almost every group. An example of normal ranges that is widely accepted by Family Practice physicians is as follows:
- Birth: 13.5 to 24.0 g/dl
- Age < 1 month: 10.0 to 20.0 g/dl
- Age 1-2 months: 10.0 to 18.0 g/dl
- Age 2-6 months: 9.5 to 14.0 g/dl
- Age 0.5 to 2 years: 10.5 to 13.5 g/dl
- Age 2 to 6 years: 11.5 to 13.5 g/dl
- Age 6-12 years: 11.5 to 15.5 g/dl
- Female
- Age 12-18 years: 12.0 to 16.0 g/dl
- Age > 18 years: 12.1 to 15.1 g/dl
Underlying causes that are responsible for the anemia often produce other symptoms that are more specific to the underlying cause.
How Is A Hematocrit Test Different From Other Components Of A Complete Blood Count
A complete blood count measures several components of the blood, including red blood cells, white blood cells, platelets, hematocrit and hemoglobin. Hematocrit is the percentage of your blood made up of red blood cells, calculated using the volume and size of RBCs. Simply stated hematocrit defines the viscosity of your blood, whether thick or thin.
Whereas hematocrit is the overall percentage of red blood cells in your total blood volume, hemoglobin is the iron-containing protein found in all red blood cells that gives the cells their characteristic red color. Hemoglobin enables RBCs to bind to oxygen in the lungs and carry it to tissues and organs throughout the body.
White blood cells are not related to hematocrit directly. White blood cells, also called leukocytes, are an important part of the bodys defense system. They help protect against infections and also have a role in inflammation and allergic reactions.
Platelets, also called thrombocytes, are tiny fragments of cells that are essential for normal blood clotting. The platelet count is a test that determines the number of platelets in your sample of blood.
Questions For Your Doctor About Test Results
Talking with your doctor can help you understand your hematocrit result and any next steps. You may wish to ask the following questions:
- What does my result mean for my health?
- Is there anything I can do to change my hematocrit levels?
- Is there any further testing that needs to be done based on my hematocrit levels?
Why Do Doctors Measure Hematocrit
As with hemoglobin, normal hematocrit ranges depend on age and gender, and the normal range may vary by the specific test used. Normal hematocrit levels are:
- Newborns: 55% to 68%
- One week of age: 47% to 65%
- One month of age: 37% to 49%
- Three months of age: 30% to 36%
- One year of age: 29% to 41%
- Ten years of age: 36% to 40%
- Adult males: 42% to 54%
- Adult women: 38% to 46%
Just as low hemoglobin levels signify anemia, a person with a low hematocrit percentage is also anemic. High hematocrit percentages are seen in the same populations that may have high hemoglobin levels.
Dangerously Low Hemoglobin Levels
Some people show signs of hemoglobin levels that are dangerously low. The causes of low hemoglobin that can put your life at risk could be due to heavy blood loss, RBCs getting destroyed too quickly, or major problems in your organs.
The journal Critical Care reports that critically low levels of hemoglobin are generally classed as anything below 8 g/dL or 8.5 g/dL.
When hemoglobin levels fall so low, doctors may have to put off surgery and raise hemoglobin levels. In critical cases, doctors may have to order a blood transfusion to increase levels of hemoglobin.7
However, some doctors say that, in some cases, the trigger point for a blood transfusion could be a low as 7.0 g/dL.
Platelet Counts Assessing Your Bodys Ability To Clot Blood
A CBC includes the number of platelets and the mean platelet volume . MPV is a measurement of the average size of the platelets. A higher MPV roughly indicates better platelet function. Some medical conditions are associated with a high MPV and some are associated with a low MPV. Thus, the MPV can sometimes be helpful in telling apart different disorders.
A decreased number of platelets is associated with bleeding. Some causes include certain rare inherited disorders, leukemia, autoimmune disorders and medications. A falsely low platelet count, which is not associated with bleeding, can be caused by a rare error in blood sample collection: instead of staying in a liquid form, the sample clots , thus using up the platelets.
An increased platelet count is less common and is associated with clotting disorders such as thrombocythemia. Platelet counts can also be increased in some cancers and following infections or other medical conditions.
Aspirin can decrease the platelet function, so its important to consult with your doctor when taking large amounts of aspirin or when taking aspirin for an extended period of time. Many over-the-counter medications contain aspirin, which may be listed as acetylsalicylic acid, salicylate, or 2- benzoic acid.
What To Do For Low Hematocrit Levels / How To Increase Hematocrit Levels
People with extremely low red blood cell counts may need to go to the doctor to get intravenous iron or blood transfusions. If theres an underlying health condition thats causing the body to produce less red blood cells, then medication might be needed to help stimulate the production of new red blood cells.
Some lifestyle changes can help increase red blood cell counts. Eating a variety of fresh, healthy foods that contain iron, vitamin B-12, and folic acid can prevent anemia. Taking these nutrients in supplement form can also be beneficial.
The best way to learn more about how to treat low or high hematocrit levels is to talk with your doctor or healthcare provider.
What About Hemoglobin A1c
When having blood work done, you might also see results for hemoglobin A1c , sometimes called glycated hemoglobin. An HbA1c test measures the amount of glycated hemoglobin, which is hemoglobin that has glucose attached to it, in your blood.
Doctors often order this test for people with diabetes. It helps to give a clearer picture of someones average blood glucose levels over the course of 2 to 4 months. Glucose, also called blood sugar, circulates throughout your blood and attaches to hemoglobin.
The more glucose in your blood, the more likely you are to have higher levels of glycated hemoglobin. The glucose stays attached to the hemoglobin for about 120 days. A high HbA1c level indicates that someones blood sugar has been high for several months.
In most cases, someone with diabetes should aim for an HbA1c level of 7 percent or less. Those without diabetes tend to have HbA1c levels of about 5.7 percent. If you have diabetes and a high HbA1c level, you may need to adjust your medication.
What Does Hematocrit Mean
Hematocrit is the percentage by volume of red cells in your blood. Blood is made up of red blood cells, white blood cells and platelets, suspended in plasma. Together, those comprise about 45% of the volume of our blood, but the specific percentages of each can vary.
What Is a Hematocrit Level?
Hematocrit level is simply the percentage of red cells in your blood. For example, a level of 38% is considered the minimum needed for donating blood.
What Is Normal Hematocrit?
Normal hematocrit levels vary based on age and race.. In adults, normal levels for men range from 41%-50%. For women, the normal range is slightly lower: 36%-44%. A hematocrit level below the normal range, meaning the person has too few red blood cells, is called anemia. A hematocrit level above the normal range, meaning too many red blood cells, may indicate polycythemia or erythrocytosis.
Why Should You Test Hematocrit Levels?
Your doctor may test your hematocrit levels if you show signs of having anemia, polycythemia or erythrocytosis. Symptoms of anemia include fatigue, shortness of breath and dizziness. Symptoms of polycythemia include fatigue, itching, headaches, and sweating. Symptoms of erythrocytosis includes headaches, dizziness, shortness of breath, and nosebleeds.
What Is the Difference Between Hematocrit and Hemoglobin
Hematocrit and hemoglobin measurements are both blood tests but they are not testing the same thing.
Hematocrit
Red Blood Cells Transporting Oxygen Throughout The Body
RBCs play a vital role in transporting oxygen from the lungs to the rest of the body. These oval-shaped cells contain hemoglobin, the protein that binds oxygen while it is being carried to all the stationary cells in the body . The chemical process that converts the nutrients found in food into energy requires oxygen. All the stationary cells require energy to function thus, they need oxygen and are dependent on the RBCs to transport it.
What Should I Expect During A Complete Blood Count
You dont need to do anything to prepare for a CBC. Your provider cleans your arm and inserts a needle. The needle may sting or pinch a little, but it shouldnt hurt. In infants, providers usually insert the needle into the babys heel.
Through the needle, your provider removes a sample of your blood and collects it in a tube. Sometimes, your provider takes more than one tube of blood.
After drawing blood, your provider removes the needle and places a bandage on your arm. Your provider sends the blood to a lab. Your body quickly rebuilds its blood supply.
What Does A Cbc Look For
A CBC does many tests to measure and study red blood cells, white blood cells and platelets. Red blood cells carry oxygen throughout the body. White blood cells are part of your immune system. They help your body fight infection. Platelets help your body clot.
A CBC measures, counts, evaluates and studies many aspects of your blood:
- CBC without differential counts the total number of white blood cells.
- CBC with differential. There are five kinds of white blood cells. The differential looks at how many of each kind of white blood cell you have.
- Hemoglobin tests measure hemoglobin, the protein in red blood cells that carries oxygen.
- Hematocrit describes the concentration of red blood cells in your blood.
A CBC tells your provider:
- How many new blood cells your body is creating.
- Number of red blood cells , white blood cells and platelets.
- Size and shape of blood cells.
What Is The Normal Range Of Hematocrit
The normal values for hematocrit vary with age and gender:
Adult men: 40 – 54%Boys over 15 years old: 40 – 51%Girls over 15 years old: 36 – 45%Children from 12 to 14 years old: 36 – 47%Children from 5 to 12 years old: 35 – 44%Children from 6 months to 5 years old: 33 – 44%Children from 2 weeks to 6 months old: 27 – 45%Newborns: 44 – 56%
The Differential Visualizing The Cells
When performing a differential, a medical technologist looks at the various cells under a microscope. A differential provides information about the relative numbers of each type of WBC. Such information helps the doctor determine whether an illness is caused by a bacteria, a virus, or leukemia. A differential can be used to monitor patients with allergies and to determine how a patient is recovering from an illness or responding to therapy.
In addition to the cell types listed previously, certain cell types that dont normally appear in the blood can be reported in the differential. These cells include promyelocytes, metamyelocytes, blasts, etc. Presence of any of these cells indicates a need for follow-up with your doctor.Finally, the differential can provide information about the appearance of RBCs, since the cells are visualized under a microscope. The appearance of RBCs helps differentiate the various types of anemia.
What Abnormal Results Mean
Low hematocrit may be due to:
- Anemia
- Destruction of red blood cells
- Leukemia
- Too little iron, folate, vitamin B12, and vitamin B6 in the diet
- Too much water in the body
High hematocrit may be due to:
- Congenital heart disease
- Failure of the right side of the heart
- Too little water in the body ( dehydration
- Low levels of oxygen in the blood
- Scarring or thickening of the lungs
- Bone marrow disease that causes abnormal increase in red blood cells
Hemoglobin Levels: High Low And Normal Range: The Complete Guide
Jenny Hills, Nutritionist and Medical Writer Health
Hemoglobin is a protein found in red blood cells which is required to transport oxygen throughout the body. Your blood needs hemoglobin levels to be in the normal range to provide oxygen to the cells in your body. Low hemoglobin levels result in various types of anemia which can cause symptoms like fatigue, dizziness, headaches, and shortness of breath. High levels of hemoglobin are less common and can also result in similar symptoms to low hemoglobin in the blood.
Vitamin and mineral deficiencies in your diet, blood loss, thyroid disorders, and pregnancy are some of the causes of low hemoglobin levels and anemia. In order to treat abnormally low hemoglobin levels, youll need to know the type of anemia you have and what caused it. Very often, iron or vitamin B12 supplements help to increase hemoglobin levels in the blood.
In this article, I will look at the medical reasons why hemoglobin levels in your blood can be below or above the normal range. You will also find out how to increase low hemoglobin levels with diet or by taking supplements.
When Should I Call My Doctor
Your provider will review the results of your CBC with you. If you have questions about the results, call your provider.
A note from Cleveland Clinic
Healthcare providers use complete blood counts to manage disease and help you stay healthy. With one sample of blood, CBCs can help screen for hundreds of disorders, conditions and infections. A CBC can detect conditions early, sometimes before you have symptoms, so treatment can start as soon as possible. CBCs are an essential tool in maintaining good overall health.
Last reviewed by a Cleveland Clinic medical professional on 03/02/2021.
References
What Is Hemoglobin
Hemoglobin is a protein found in red blood cells that is responsible for carrying oxygen around the body.
Doctors on MedicineNet say that each hemoglobin molecule contains iron compounds that also give blood its distinct red color. When red blood cells die off, the iron gets absorbed into the bone marrow and helps to produce new red blood cells . Leftover hemoglobin turns into bilirubin and goes into the digestive bile. This is the chemical that is responsible for the color of your stool.1
Why It Is Done
A complete blood count may be done to:
- Find the cause of symptoms such as fatigue, weakness, fever, bruising, or weight loss.
- Check for anemia.
- Diagnose diseases of the blood, such as leukemia.
- Check how the body is dealing with some types of drug or radiation treatment.
- Check how abnormal bleeding is affecting the blood cells and counts.
- Screen for high and low values before a surgery.
- See if there are too many or too few of certain types of cells. This may help find other conditions, such as too many eosinophils may mean an allergy or asthma is present.
A complete blood count may be done as part of a regular physical examination. A blood count can give valuable information about the general state of your health.
Symptoms Of Low Hematocrit Levels
Having low hematocrit levels, which is sometimes called anemia, often makes people feel under the weather. If youre having any of the following symptoms, they could mean you have a low red blood cell count:
- Tiredness
- Not enough oxygen in the blood
- Erythrocytosis
Having abnormally high levels of red blood cells doesnt necessarily mean that you have one of the conditions listed above. High hematocrit levels can mean that you might have a serious health condition like heart disease, but your doctor will run other tests to make sure youre properly diagnosed.
Why The Test Is Performed
The hematocrit is almost always done as part of a complete blood count .
Your health care provider may recommend this test if you have signs of or are at risk for anemia. These include having:
- Grumpiness or tiredness
- Blood in your stools, or vomit
- Treatment for cancer
- Leukemia or other problems in the bone marrow
- Chronic medical problems, such as kidney disease or certain types of arthritis