Hemoglobin and Hematocrit

The Hemoglobin and Hematocrit test contains 1 test with 2 biomarkers.

Brief Description: The Hemoglobin and Hematocrit test is a routine blood test that measures the levels of hemoglobin and hematocrit in the blood. These two parameters provide valuable information about a person's red blood cell (RBC) count and the ability of blood to carry oxygen. Hemoglobin is the protein in RBCs responsible for carrying oxygen, while hematocrit is the proportion of RBCs in the blood compared to the total blood volume.

Also Known As: HCT Test, Crit Test, Packed Cell Volume Test, PCV Test, Hb Test, Hgb Test

Collection Method: Blood Draw

Specimen Type: Whole Blood

Test Preparation: No preparation required

When is a Hemoglobin and Hematocrit test ordered?

A Hemoglobin and Hematocrit test is commonly ordered as part of a complete blood count (CBC) during routine health check-ups, pre-surgical evaluations, and to monitor certain medical conditions. It may also be ordered when a patient presents with symptoms such as fatigue, weakness, dizziness, or suspected anemia.

What does a Hemoglobin and Hematocrit blood test check for?

A hematocrit is a test that determines the percentage of red blood cells in a person’s blood. RBCs, white blood cells, and platelets are suspended in plasma, a fluid component of blood. The hematocrit is a ratio that compares the volume of red blood cells to the volume of all of these components together, which is known as whole blood. A percentage or fraction is used to express the value. A hematocrit of 40%, for example, indicates that there are 40 milliliters of red blood cells per 100 milliliters of blood.

The hematocrit is a quick and easy approach to assess a person’s red blood cells and screen for disorders like anemia. It’s frequently done in conjunction with a hemoglobin level, and it’s also a part of a complete blood count, which is commonly used to assess a person’s overall health.

RBCs are made in the bone marrow and discharged into the bloodstream when they are fully mature or almost so. They normally constitute about 37 to 49 percent of the blood volume. Hemoglobin, a protein that binds to oxygen, is found in RBCs. RBCs’ main job is to transport oxygen from the lungs to the body’s tissues and organs. They also transfer a little amount of carbon dioxide from tissues and organs back to the lungs, where it is exhaled.

RBCs have a 120-day lifespan, and the bone marrow must constantly manufacture new RBCs to replace those that have aged and degraded or have been lost due to hemorrhage. A variety of disorders can impact the bone marrow’s ability to produce new RBCs or the longevity of those already in circulation, as well as cause substantial bleeding.

The hematocrit measures both the number and volume of red blood cells. The hematocrit will drop when the size of the RBCs decreases, and vice versa. In general, the hematocrit will rise as the number of red blood cells increases, and it will fall to less than normal when the number of RBCs produced by the bone marrow decreases, the number of RBCs destroyed increases, or blood is lost due to hemorrhage. The overall amount of RBCs and hematocrit will diminish if the bone marrow is unable to manufacture new RBCs quickly enough, resulting in anemia.

Anemia is a condition in which the body is unable to provide adequate oxygen to tissues and organs, resulting in weariness and weakness. Too many RBCs are created in polycythemia, and the blood thickens, causing sluggish blood flow and other complications.

Hemoglobin is an iron-containing protein found in all red blood cells, which gives them their distinctive red color. RBCs use hemoglobin to bind to oxygen in the lungs and transport it to tissues and organs all over the body. It also aids in the movement of a little amount of carbon dioxide, which is a byproduct of cell metabolism, from tissues and organs to the lungs, where it is exhaled.

The hemoglobin test determines how much hemoglobin is present in a person's blood sample. To swiftly assess an individual's red blood cells, a hemoglobin level can be used alone or in conjunction with a hematocrit, a test that assesses the fraction of blood made up of RBCs. Red blood cells, which account for roughly 40% of the amount of blood, are created in the bone marrow and released into the bloodstream when they are mature, or nearly so. RBCs have a 120-day lifespan, and the bone marrow must constantly manufacture new RBCs to replace those that have aged and degraded or have been lost due to hemorrhage.

RBCs, and thus the level of hemoglobin in the blood, can be affected by a variety of diseases and situations. When the quantity of red blood cells grows, the hemoglobin level and hematocrit both rise. When the synthesis of RBCs by the bone marrow decreases, RBC destruction increases, or blood is lost owing to hemorrhage, the hemoglobin level and hematocrit fall below normal. Anemia is a disorder in which the body's tissues and organs do not acquire enough oxygen, causing exhaustion and weakness. It is caused by a decline in RBC count, hemoglobin, and hematocrit. Polycythemia occurs when the body produces too many RBCs, causing the blood to thicken, resulting in sluggish blood flow and other complications.

Lab tests often ordered with a Hemoglobin and Hematocrit test:

When these tests are ordered, they're typically part of a broader evaluation of blood health or specific symptoms like fatigue or weakness. Here are some tests commonly ordered alongside Hemoglobin and Hematocrit:

1. Complete Blood Count (CBC):

   • Purpose: Provides a comprehensive overview of blood health, including white and red blood cells, platelets, and other parameters.
   • Why Is It Ordered: To assess overall blood health, diagnose anemia, polycythemia, infection, inflammation, and other blood disorders.

2. Iron Studies:

   • Purpose: To evaluate body iron stores and iron utilization.
   • Why Is It Ordered: To diagnose iron deficiency anemia or iron overload conditions like hemochromatosis.

3. Vitamin B12 and Folate Test:

   • Purpose: To measure levels of these essential vitamins.
   • Why Is It Ordered: To identify deficiencies that can lead to certain types of anemia, such as megaloblastic anemia.

4. Reticulocyte Count:

   • Purpose: To measure the number of young red blood cells in the blood.
   • Why Is It Ordered: To assess bone marrow function and the body’s response to anemia.

5. Kidney Function Test:

   • Purpose: To evaluate kidney function.
   • Why Is It Ordered: Kidney disease can impact the production of erythropoietin, a hormone that stimulates red blood cell production, affecting hemoglobin and hematocrit levels.

6. Liver Function Test:

   • Purpose: To assess liver health.
   • Why Is It Ordered: Liver diseases can influence overall health, including the metabolism of nutrients essential for blood cell production.

These tests, when ordered alongside Hemoglobin and Hematocrit, provide a comprehensive view of an individual’s blood health and can help diagnose, monitor, and manage a variety of conditions related to red blood cells. They are particularly useful in determining the cause of anemia, assessing the effectiveness of treatments, and monitoring conditions that affect red blood cell production and lifespan. The specific combination of tests will depend on the individual's symptoms, medical history, and the results of the initial tests.

Conditions where a Hemoglobin and Hematocrit test is recommended:

A Hemoglobin and Hematocrit test is essential for the evaluation of various conditions, including:

1. Anemia: The test is crucial for diagnosing and monitoring different types of anemia, such as iron deficiency anemia, vitamin deficiency anemia, hemolytic anemia, and others.

2. Blood Loss: In cases of acute or chronic blood loss, the test can help determine the extent of RBC loss and guide appropriate management.

3. Chronic Diseases: Some chronic diseases or conditions can affect RBC production and lead to changes in hemoglobin and hematocrit levels.

How does my health care provider use a Hemoglobin and Hematocrit test?

Healthcare providers use the results of a Hemoglobin and Hematocrit test to:

1. Diagnose Anemia: Abnormal levels of hemoglobin and hematocrit can indicate the presence of anemia and help determine its underlying cause.

2. Monitor Anemia Treatment: For individuals with anemia, the test is used to monitor the effectiveness of treatment, such as iron supplementation or vitamin therapy.

3. Assess Overall Blood Health: The test provides valuable information about a person's overall blood health and can aid in the diagnosis of various blood-related conditions.

4. Guide Further Evaluation: Abnormal results may prompt healthcare providers to order additional tests to pinpoint the exact cause of the abnormality and provide appropriate medical care.

In summary, the Hemoglobin and Hematocrit test is a simple yet critical blood test that helps assess a person's RBC count and oxygen-carrying capacity, aiding in the diagnosis and monitoring of anemia and other blood-related conditions.

What do my Hematocrit and Hemoglobin test results mean?

Red blood cells make up between 37 percent to 49 percent of the total amount of blood.

Because a hematocrit is frequently performed as part of a complete blood count, other components including RBC count, hemoglobin, reticulocyte count, and/or red blood cell indices are taken into account. Other considerations include age, gender, and race. In general, the hematocrit reflects the RBC count and hemoglobin readings.

Anemia is diagnosed by a low hematocrit, low RBC count, and low hemoglobin.

Because hemoglobin levels are frequently measured as part of a complete blood count, the results of other components are taken into account. Hemoglobin levels must be interpreted in conjunction with other indicators such as RBC count, hematocrit, reticulocyte count, and/or red blood cell indices when they rise or fall. Other characteristics to consider are age, gender, and race. Hemoglobin reflects the RBC count and hematocrit results in general.

Anemia is defined as a low hemoglobin level combined with a low RBC count and a low hematocrit. Among the causes are:

• Excessive blood loss-as a result of severe trauma or continuous bleeding from the digestive tract, bladder, or uterus.
• Iron, folate, or B12 deficiency are examples of nutritional inadequacies.
• Toxins, radiation, chemotherapy, infection, and medicines can all cause damage to the bone marrow.
• Aplastic anemia, myelodysplastic syndrome, or tumors of the bone marrow, such as leukemia, lymphoma, multiple myeloma, or other cancers of the bone marrow
• Renal failure—severe and chronic kidney illnesses cause the kidneys to produce less erythropoietin, a hormone that drives RBC synthesis in the bone marrow.
• Inflammatory diseases or disorders that last a long time
• Hemoglobin production is reduced.
• Excessive destruction of red blood cells, such as hemolytic anemia caused by autoimmunity or faults in the red blood cell itself, such as hemoglobinopathy, RBC membrane abnormalities, or RBC enzyme.

Polycythemia is defined as a high hemoglobin level combined with a high RBC count and hematocrit. Among the causes are:

• Lung disease-when a person's body is unable to breathe in and absorb enough oxygen. As a result, the body produces more red blood cells to compensate.
• Congenital heart disease—in some cases, an improper connection between the two sides of the heart occurs, resulting in lower blood oxygen levels. The body responds by creating extra red blood cells in an attempt to compensate.
• Excess erythropoietin-producing kidney tumors
• Hemoglobin levels in heavy smokers are higher than in nonsmokers.
• Genetic factors
• Having to live at a high altitude
• Dehydration causes hemoglobin to rise unnaturally when the volume of fluid in the blood declines.
• Polycythemia vera-a rare condition in which the body creates too many RBCs.

Most Common Questions About the Hemoglobin and Hematocrit test:

Understanding the Hemoglobin and Hematocrit Test

What is the Hemoglobin and Hematocrit test?

The Hemoglobin and Hematocrit test is a common blood test that measures the levels of hemoglobin and hematocrit in your blood. Hemoglobin is a protein in your red blood cells that carries oxygen, and hematocrit is the proportion of your total blood volume that is made up of red blood cells.

Why would a healthcare provider order a Hemoglobin and Hematocrit test?

A healthcare provider may order this test as part of a complete blood count (CBC) to evaluate your overall health, to diagnose a medical condition, to monitor a medical condition or to monitor medical treatment that can affect blood cell counts.

What does it mean if my Hemoglobin and Hematocrit test results are high?

High Hemoglobin and Hematocrit levels could indicate various conditions such as dehydration, lung disease, or an abnormal increase in red blood cell production.

What does it mean if my Hemoglobin and Hematocrit test results are low?

Low Hemoglobin and Hematocrit levels often indicate you have a low red blood cell count (anemia). This could be caused by a wide variety of conditions such as vitamin deficiency, blood loss, or an underlying disease.

Understanding Hemoglobin and Hematocrit in the Body

What role do hemoglobin and hematocrit play in the body?

Hemoglobin carries oxygen from the lungs to the rest of the body and returns carbon dioxide from the body to the lungs so it can be exhaled. Hematocrit represents the percentage of the volume of whole blood that is made up of red blood cells, which directly affects the blood's capacity to carry oxygen.

What factors could affect the levels of hemoglobin and hematocrit in my body?

Many factors can affect the levels of hemoglobin and hematocrit, including your diet, your overall health, and certain medications. For instance, low vitamin B12 or folate levels can cause low hemoglobin. Dehydration can make hematocrit levels appear higher, as there's less plasma in your blood.

Understanding Test Results and Follow-ups

What does it mean if my Hemoglobin and Hematocrit test results are in the normal range?

If your Hemoglobin and Hematocrit test results are in the normal range, it usually means that you have an appropriate number of red blood cells and that these cells contain enough hemoglobin to properly transport oxygen.

What factors can affect my Hemoglobin and Hematocrit test results?

Factors that can affect Hemoglobin and Hematocrit test results include dehydration, recent blood loss, recent transfusion, high altitude, pregnancy, and certain medications.

What should I do if my Hemoglobin and Hematocrit test results are abnormal?

If your Hemoglobin and Hematocrit test results are abnormal, your healthcare provider will likely order additional tests to determine the cause of the abnormal results and will recommend appropriate treatment based on the findings.

Are there certain conditions or diseases that the Hemoglobin and Hematocrit test can specifically diagnose?

While the Hemoglobin and Hematocrit test can't specifically diagnose a disease, it can indicate if there is a problem that requires further testing. For example, abnormal results may suggest anemia, dehydration, or a blood disorder that requires further investigation.

Hemoglobin and Hematocrit Tests and Specific Populations

How might Hemoglobin and Hematocrit test results differ in people who are pregnant?

During pregnancy, a woman's blood volume increases, which can lead to a decrease in hemoglobin concentration and hematocrit, even though the total number of red blood cells and amount of hemoglobin are actually increasing.

How might Hemoglobin and Hematocrit test results differ in older adults?

As people age, they may experience changes in their red blood cells that can affect Hemoglobin and Hematocrit levels. For example, kidney function declines with age, which can lead to a decreased production of erythropoietin, a hormone that stimulates red blood cell production, leading to lower hemoglobin and hematocrit levels.

Can the Hemoglobin and Hematocrit test be used to monitor the effectiveness of treatment for conditions like anemia?

Yes, the Hemoglobin and Hematocrit test is often used to monitor the effectiveness of treatments for anemia and other conditions that affect red blood cells. If you're being treated for such a condition, your doctor may order these tests frequently to track your progress.

General Questions About the Test

What conditions or symptoms might warrant a Hemoglobin and Hematocrit test?

Conditions or symptoms that might warrant a Hemoglobin and Hematocrit test include fatigue, weakness, shortness of breath, dizziness, or a pale complexion. These symptoms can indicate anemia, which would result in lower than normal hemoglobin and hematocrit levels.

How often should a Hemoglobin and Hematocrit test be done?

There's no set frequency for a Hemoglobin and Hematocrit test. It's typically done as needed, based on symptoms, risk factors, and the healthcare provider's discretion.

What should I do to prepare for a Hemoglobin and Hematocrit test?

Generally, no special preparation is needed for a Hemoglobin and Hematocrit test. However, you should always follow your healthcare provider's specific instructions.

Can the Hemoglobin and Hematocrit test tell me if I have a blood disorder?

While the Hemoglobin and Hematocrit test can't diagnose a specific blood disorder, it can indicate if there's a problem with your red blood cells that needs further investigation.

Can a Hemoglobin and Hematocrit test detect blood cancers like leukemia?

While a Hemoglobin and Hematocrit test can't diagnose leukemia or other blood cancers, abnormal results can be a sign that there's a problem with your blood cells that needs further investigation.

Can the Hemoglobin and Hematocrit test be used to monitor my response to certain treatments like chemotherapy or radiation therapy?

Yes, the Hemoglobin and Hematocrit test can be used to monitor your body's response to treatments like chemotherapy or radiation therapy, which can affect your red blood cells.

How are Hemoglobin and Hematocrit levels affected by bone marrow conditions?

Bone marrow conditions, such as aplastic anemia or bone marrow cancers, can affect the production of red blood cells, and therefore hemoglobin and hematocrit levels.

Can Hemoglobin and Hematocrit test results be affected by high altitudes?

Yes, living at high altitudes can cause an increase in hemoglobin and hematocrit levels. This is a normal adaptation to the lower oxygen levels present at high altitudes.

Can a Hemoglobin and Hematocrit test tell me if I am dehydrated?

While the Hemoglobin and Hematocrit test is not a direct measure of hydration status, if you are dehydrated, your hematocrit levels may be higher than normal because your blood plasma volume is reduced.

Can a Hemoglobin and Hematocrit test help detect kidney disease?

Chronic kidney disease can result in decreased production of erythropoietin, a hormone that stimulates the production of red blood cells. This can result in a decrease in hemoglobin and hematocrit levels, so while the test can't diagnose kidney disease, it can indicate a problem that needs further investigation.

How does iron deficiency affect Hemoglobin and Hematocrit test results?

Iron deficiency can lead to a decrease in hemoglobin, as iron is a key component of hemoglobin. As a result, both hemoglobin and hematocrit levels can be lower in people with iron deficiency.

How does vitamin B12 or folate deficiency affect Hemoglobin and Hematocrit test results?

Vitamin B12 and folate are necessary for the production of red blood cells. A deficiency in either can lead to a type of anemia called megaloblastic anemia, where the body produces fewer, but larger, red blood cells, resulting in lower hemoglobin and hematocrit levels.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.