Haptoglobin

The Haptoglobin test contains 1 test with 1 biomarker.

Brief Description: The Haptoglobin test is a specialized laboratory assay designed to measure the concentration of haptoglobin—a glycoprotein—present in the blood. Haptoglobin plays a vital role in binding free hemoglobin released from red blood cells during their breakdown. By forming haptoglobin-hemoglobin complexes, it prevents hemoglobin from causing damage to tissues and kidneys.

Also Known As: HPT Test, Hemoglobin-binding Protein Test, Hp Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: Overnight fasting is preferred

When is a Haptoglobin test ordered?

When someone exhibits symptoms and/or indicators of hemolytic anemia, a haptoglobin test is prescribed. Several symptoms and indicators include:

  • drowsiness, weakness
  • Pale skin Growing weak
  • breathing difficulty
  • a quick heartbeat
  • Jaundice
  • brown or red urine

The results of further laboratory tests that are consistent with hemolytic anemia may also warrant testing. These could exhibit elevated bilirubin levels, urine hemoglobin, a decrease in RBC count, an increase in reticulocyte count, and elevated lactate dehydrogenase values.

What does a Haptoglobin blood test check for?

The body employs the protein haptoglobin, which is made by the liver, to remove free hemoglobin from circulation. The amount of haptoglobin in the blood is determined by this test.

The protein complex called hemoglobin, which contains iron, carries oxygen throughout the body. It rarely circulates freely in the blood and is typically present inside red blood cells. In the blood, haptoglobin binds to free hemoglobin. A haptoglobin-hemoglobin complex is created, which is quickly removed from circulation for haptoglobin breakdown and iron recycling.

However, as more RBCs sustain injury or fragmentation, more hemoglobin is released into the blood, increasing the amount of free hemoglobin in circulation. Haptoglobin levels in the blood will temporarily drop when a significant amount of RBCs are destroyed because haptoglobin is eaten up more quickly than the liver can generate it. A disorder that causes red blood cells to be damaged or break apart may be indicated by a reduction in haptoglobin levels. The level of free hemoglobin in the blood increases when haptoglobin's binding capacity is surpassed, which may result in tissue damage and organ failure.

Conditions that are inherited or acquired may increase RBC oxidation. Examples include transfusion reactions, specific medications, and mechanical failure, which can occur with some artificial heart valves. Hemolytic anemia can result from the destruction, which can be minor or severe, rapid or gradual, and mild or long-lasting. People who have hemolytic anemia may exhibit symptoms like weakness, exhaustion, and shortness of breath, as well as pale or jaundiced skin.

As liver impairment may prevent both the formation of haptoglobin and the clearance of the haptoglobin-free hemoglobin complexes, liver disease may also cause decreased haptoglobin concentrations.

Lab tests often ordered with a Haptoglobin test:

When a Haptoglobin test is ordered, it's typically part of a broader evaluation of hemolysis and anemia. Here are some tests commonly ordered alongside it:

  1. Complete Blood Count (CBC) with Differential:

    • Purpose: To evaluate overall blood health, including red and white blood cells, hemoglobin, hematocrit, and platelets.
    • Why Is It Ordered: To assess for anemia and other blood cell abnormalities. A low hemoglobin level with a high reticulocyte count may suggest hemolysis.
  2. Lactate Dehydrogenase (LDH):

    • Purpose: To measure the level of LDH, an enzyme found in many body tissues, including red blood cells.
    • Why Is It Ordered: LDH levels can be elevated in hemolytic anemia, indicating red blood cell destruction.
  3. Reticulocyte Count:

    • Purpose: To count young red blood cells (reticulocytes).
    • Why Is It Ordered: A high reticulocyte count indicates that the bone marrow is producing more red blood cells to replace those being destroyed.
  4. Direct Antiglobulin Test (DAT, Coombs Test):

    • Purpose: To detect antibodies that are bound to the surface of red blood cells.
    • Why Is It Ordered: To determine whether hemolysis is immune-mediated, as seen in autoimmune hemolytic anemia.
  5. Serum Iron, Ferritin, and Total Iron-Binding Capacity (TIBC):

    • Purpose: To evaluate iron metabolism.
    • Why Is It Ordered: To assess iron status, which can be affected by hemolytic anemia and its treatment.

These tests, when ordered alongside a Haptoglobin test, provide a comprehensive evaluation of hemolytic anemia and its underlying causes. They are crucial for diagnosing and managing hemolytic anemia, determining the mechanism of red blood cell destruction, and guiding appropriate treatment. The specific combination of tests will depend on the individual’s symptoms, clinical presentation, and medical history.

Conditions where a Haptoglobin test is recommended:

The Haptoglobin test is essential for diagnosing and monitoring various conditions, including:

  1. Hemolytic Anemia: Decreased haptoglobin levels can be indicative of hemolysis, a condition where red blood cells are destroyed prematurely.

  2. Inflammation: Elevated haptoglobin levels can be associated with inflammation and tissue damage, often observed in conditions like infection and autoimmune disorders.

  3. Liver Disorders: The Haptoglobin test can provide insights into liver function, as haptoglobin is synthesized by the liver.

How does my health care provider use a Haptoglobin test?

Testing for hemoglobin is primarily used to identify and assess hemolytic anemia and to differentiate it from anemia caused by other conditions. Testing is done to evaluate whether red blood cells are disintegrating or perishing too soon. The complete blood count, reticulocyte count, lactate dehydrogenase, bilirubin, direct antiglobulin test, and blood smear are a few examples of the lab tests that can be utilized in conjunction with it.

A rare cause of anemia is hemolytic anemia. The disorder may be hereditary or may appear over a person's lifetime as a result of a variety of events. It may appear quickly or may take time to appear.

Despite being a sensitive test for hemolytic anemia, the haptoglobin test cannot be used to determine what is causing the illness. Other laboratory tests, such as autoantibody tests to identify autoimmune reasons, sickle cell tests, G6PD tests, or a hemoglobin evaluation, can be required to help identify the cause.

If a person has undergone blood transfusions, a haptoglobin test may be requested in addition to a direct antiglobulin test to assist identify whether they experienced a transfusion reaction.

Testing may be performed later to assess concentration changes and help identify whether the accelerated destruction of RBCs is still happening or has stopped if haptoglobin levels are low.

What do my Haptoglobin test results mean?

Results from additional tests, such as a reticulocyte count, red blood cell count, hemoglobin, hematocrit, or complete blood count, are also analyzed carefully.

A person is likely to have some degree of hemolytic anemia, in which red blood cells are destroyed in the circulation, if their haptoglobin level is noticeably low, along with an elevated reticulocyte count, a decreased RBC count, hemoglobin, and hematocrit.

RBC destruction is probably happening in organs like the spleen and liver if the haptoglobin is normal or borderline normal and the reticulocyte count is elevated. The haptoglobin is not consumed since the liberated hemoglobin is not released into the blood, hence its level is normal. Haptoglobin levels, however, may be low in severe extravascular hemolysis because excess hemolysis might release some free hemoglobin into the bloodstream.

It is likely that the anemia seen is not caused by RBC breakdown if the haptoglobin level is normal and the reticulocyte count is not elevated.

Most Common Questions About the Haptoglobin test:

Purpose and Indications for the Haptoglobin Test

Why is the Haptoglobin test ordered?

The Haptoglobin test is primarily ordered to help evaluate and monitor hemolytic anemia. Haptoglobin binds free hemoglobin released from erythrocytes, preventing kidney damage. When hemolysis occurs, haptoglobin levels decrease.

Is the Haptoglobin test specific for hemolytic anemia?

While the Haptoglobin test is a strong indicator of hemolysis, it isn't exclusive to hemolytic anemia. Low haptoglobin levels can also be seen in conditions like liver disease, malnutrition, and inflammation.

Clinical Significance of Test Results

What do low levels in the Haptoglobin test indicate?

Low haptoglobin levels suggest increased hemolysis or breakdown of red blood cells. This might be due to conditions like hemolytic anemia, transfusion reactions, or other diseases that cause premature destruction of red blood cells.

Are high haptoglobin levels a concern?

Elevated haptoglobin levels are less common and are typically associated with conditions like liver disease, inflammation, and certain types of cancer. High levels might also be seen after extensive surgery or trauma.

Interpretation and Follow-up

If the Haptoglobin test shows abnormal levels, what steps should one take next?

If the test shows abnormal levels, further evaluation is needed. A healthcare provider might order additional tests to determine the cause of the abnormality. The management and treatment would depend on the underlying condition causing the change in haptoglobin levels.

Can the Haptoglobin test be used to monitor treatment efficacy?

Yes, the Haptoglobin test can be used to monitor the effectiveness of treatments for conditions causing hemolysis. A rise in haptoglobin levels during treatment can indicate a reduction in hemolysis.

Conditions and Medications Influencing the Test

How does acute inflammation affect the Haptoglobin test?

Acute inflammation can cause an increase in haptoglobin levels. This is because haptoglobin is an acute-phase reactant, and its production can be stimulated by conditions causing inflammation.

Do any medications influence the outcome of the Haptoglobin test?

Some drugs, such as steroids, might increase haptoglobin levels, while others, like the estrogen-containing medications, might decrease them. It's essential to inform the healthcare provider of any medications being taken before undergoing the test.

Dietary Influence and Recommendations

Does alcohol consumption influence Haptoglobin levels?

Chronic alcohol consumption can lead to liver disease, which can influence haptoglobin levels. Therefore, excessive alcohol intake might indirectly affect the test results.

Is there any dietary recommendation before taking the Haptoglobin test?

There's no specific dietary recommendation before taking the test. However, it's always good to follow a balanced diet for overall health.

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

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

Also known as: Hemoglobin-binding Protein, Hp, HPT

Haptoglobin

*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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