What is the Ham test?
The Ham test is a blood test that can help your doctor determine the condition of the red blood cells in your body. Dr. Thomas Ham designed it. The test can help your doctor diagnose certain types of acquired and congenital blood disorders. It involves soaking a blood sample in mild acid to test the fragility of your blood cells.
Doctors don’t use the Ham test very often. The flow cytometry test is gradually replacing it.
One drop of your blood contains millions of red blood cells. They constantly move through your circulatory system, delivering oxygen your organs and tissues and removing waste. Healthy red blood cells are vital for your body’s organs to work properly. Their red color comes from a chemical called hemoglobin. This is a protein that carries iron and transports oxygen. Your red blood cells die around every 120 days, and your bone marrow is constantly producing new ones.
Your doctor may use this test to help diagnose paroxysmal nocturnal hemoglobinuria (PNH) or congenital dyserythropoietic anemia (CDA). These are both blood conditions.
No special preparations are necessary for this test. You should tell your doctor if you’re taking any blood thinners, such as warfarin (Coumadin). Your doctor may advise you to stop taking certain medications.
You’ll need to provide a sample of blood from your arm. This involves the following steps:
- A healthcare provider will clean the site.
- They’ll insert the needle into your vein and draw your blood into an attached tube.
- When they’ve drawn enough blood for a sample, they’ll remove the needle and bandage the site.
- They’ll then send the blood sample to a laboratory for analysis.
If the red blood cells don’t become fragile in the acid solution, your result is normal. A normal result will show as a negative reading.
The following are two conditions that can cause abnormal results:
Paroxysmal nocturnal hemoglobinuria
PNH is a rare, acquired disease, which means it’s not genetic. It causes the red blood cells to die prematurely and new cells to produce incorrectly. The red cells become sensitive to damage by another substance in the blood. This disorder affects red blood cells, white blood cells, and platelets. White blood cells fight infection. Platelets are tiny blood cells that prevent bleeding.
The United States National Library of Medicine notes that this acquired disease affects both men and women, and most commonly occurs in early adolescence. The treatment for this disorder if you have mild symptoms is folate and iron replacement. People also take steroids for it in more severe cases. In extreme cases, bone marrow transplants can treat the disorder. The disorder can cause:
- recurring infections
- dark-colored urine, particularly in the morning
- shortness of breath
- abnormally pale skin
- back pain
- abdominal pain
- an increased tendency for venous blood clots, or thrombosis
Congenital dyserythropoietic anemia
CDA rare blood disease is inherited. Doctors often include it in the group of anemias that involve reduced hemoglobin synthesis, or thalassemia. It causes a shortage of red blood cells in the body due to decreased production. This prevents the circulatory system from delivering enough oxygen to the organs and tissues. The disorder can cause:
- dizzy spells
- abnormally pale skin
- yellowing of the skin, or jaundice
- liver disease
If you have CDA, your doctor will need to determine which of the three types you have.
CDA type 1 causes mild anemia. Doctors usually diagnose it in early childhood. It can cause iron overload. The usual treatment for this type is chelation therapy, which helps remove excess iron from the body. Yellowing of the eyes and skin is common in people who have this condition.
CDA type 2 may be mild to severe. Doctors usually diagnose it in the early teens. It can lead to:
- heart disease
CDA type 3 causes relatively mild symptoms. People with this type usually receive a diagnosis during adulthood. It may lead to vision impairment and cancer of the white blood cells.
As with any blood test, this test has a minimal risk of causing minor bruising at the needle site. In rare cases, the vein may swell after blood is drawn. If this occurs, apply a warm compress to the spot several times each day. Ongoing bleeding can be a problem if you have a bleeding disorder or if you’re taking a blood thinner such as warfarin (Coumadin) or aspirin.
Blood transfusions are a common treatment for CDA. You’ll also need to take medicine to remove the excess iron that builds up in your body. In extreme cases, a bone marrow transplant may be necessary. Researchers haven’t found gene therapy to be effective for this type.
The treatment for PNH is iron and folate replacement. Your doctor may also prescribe steroids. Doctors often use warfarin (Coumadin) to treat blood clots associated with PNH because it thins the blood and reduces the risk of thrombosis. If you have an extreme case, you may need a bone marrow transplant.