What is a blood test for hemoglobin?
A blood test for hemoglobin is a measurement of the level of hemoglobin in your blood. Hemoglobin is a protein in red blood cells that carries oxygen from your lungs to other parts of your body. If your hemoglobin level is abnormal, it may be a sign that you have a blood disorder.
Other names for the blood test for hemoglobin: hemoglobin test, hb, hgb, hemoglobin meter
What is a blood test for hemoglobin used for?
A blood test for hemoglobin is usually used to check for anemia, a condition in which your body has fewer red blood cells than normal. If you have anemia, the cells in your body are not getting all the oxygen they need. A blood test for hemoglobin is measured as part of a complete blood count (CBC).
Why do I need a blood test for hemoglobin?
Your doctor may order blood test for hemoglobin as part of a routine checkup or if you have symptoms of anemia, such as
- Weakness, dizziness and cold hands and feet.
- A family history of thalassemia, sickle cell anemia or other inherited blood disorders
- Have a diet low in iron and other minerals
- Chronic infections
- Excessive blood loss due to injury or surgery
When should I have my hemoglobin tested?
Hemoglobin is one indicator of how much oxygen your body is getting. Hemoglobin levels can reflect whether you have enough iron in your blood. Therefore, if you are experiencing signs and symptoms of low oxygen or low iron, your provider may order a complete blood count to measure hemoglobin. These symptoms may include:
- Fatigue
- Shortness of breath during physical activity
- Paler or more yellowish skin than usual
- Headache, dizziness
- Irregular heart rhythm
Although less common, high hemoglobin levels can cause health problems. If you have signs of abnormally high hemoglobin levels, such as:
- Visual impairment
- Dizziness
- Headaches
- Slurred speech
- a reddening of the face
You may need to order a blood test for hemoglobin if you have been diagnosed with, or suspect, any of the following:
- Blood disorders, such as sickle cell disease or thalassemia
- Diseases affecting the lungs, liver, kidneys or cardiovascular system
- Heavy bleeding from trauma or surgery
- Malnutrition or a diet low in vitamins and minerals, especially iron
- Significant long-term infections
- Cognitive impairment, especially in the elderly
- Certain types of cancer
Can I take the blood test for hemoglobin at home?
There are several options for home blood test for hemoglobin testing. The at-home test uses one or more drops of blood to estimate hemoglobin levels. The blood drops are obtained by pricking your finger with a fine needle.
The results of a home blood test for hemoglobin test with proper certification will not differ much from the results of a laboratory test, but may not be applicable for some patients. There are now many clinics and private physicians who choose home hemoglobin meters to help patients measure their hemoglobin levels.
Your physician can help you understand if your condition is suitable for home testing.
What happens during a blood test for hemoglobin?
- The first is that a health care provider will take a blood sample from a vein in your arm using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little tingling as the needle is inserted or removed. This usually takes less than 5 minutes.
- The second is for you to poke your fingertips at home with a willow needle, take a 10ul blood sample with a blood collection tube, and test your anemia with a blood test for hemoglobin meter.
Do I need to prepare for the blood test for hemoglobin?
You do not need to do any special preparation for the hemoglobin test. If your doctor orders other tests on your blood sample, you may need to fast (not eat or drink) for a few hours before the test. Your doctor will let you know if there are any special instructions to follow.
Are there any risks associated with the blood test for hemoglobin?
The risks of having a blood test for hemoglobin are very small. After the blood test for hemoglobin, some people have mild pain, dizziness or bruising. These symptoms usually go away quickly.
There is even less risk with the at-home blood test for hemoglobin because no large amounts of blood are needed, just fingertip blood, which heals quickly.
Receiving blood test for hemoglobin results
If you are having the blood test for hemoglobin done in a hospital, the results of the hemoglobin test are usually available within a few days after your blood is drawn. You may receive your results by mail or electronically. Your doctor's office may also contact you to discuss the results of your test.
For tests performed at home, you will get your results in a short period of time
Interpreting blood test for hemoglobin results
Hemoglobin results are measured in volume. The numbers associated with your result are in grams per deciliter or g/dL, but the test report may not have “g/dL” listed after the number. For example, your test result may be written as 14 or 14 g/dL.
Normal hemoglobin reference ranges may vary depending on several factors, including age, sex, ethnicity, pregnancy status, genetics, the altitude at which you live, and lifestyle choices.
The high and low values of a normal test result, called the reference range, may differ depending on the laboratory and the methods used to conduct the test. For this reason, it is essential to look at the reference range listed on your test report.
An example of potential reference range, provided by the American Board of Internal Medicine, is listed in the following tables:
| HEMOGLOBIN REFERENCE RANGE FOR ADULTS | |
|---|---|
| SEX | REFERENCE RANGE |
| Adult Female | 12 to 16 g/dL |
| Adult Male | 14 to 18 g/dL |
| HEMOGLOBIN REFERENCE RANGE NEWBORNS AND INFANTS | |
|---|---|
| AGE | REFERENCE RANGE |
| Newborn (birth to 2 months) | 14 to 24 g/dL |
| Infant (2 months to 1 year) | 9.5 to 13 g/dL |
While these provide an example of a potential reference range, anyone's results can only be considered abnormal based on the range of instruments performing the test.
Since hemoglobin is affected by many factors, it is important that you discuss your results with your physician or contact the hemoglobin meter product vendor if you have any concerns about your results. Only they can clarify whether your hemoglobin test results are normal for your condition.
If your hemoglobin level is low, it may be a sign of anemia. There are many potential causes of anemia, including blood loss, nutritional deficiencies and many other conditions.
High hemoglobin can also be a sign of an underlying health problem, including diseases that affect the lungs and heart. Dehydration, smoking, living at high altitude, and some genetic disorders can also lead to high hemoglobin levels.
An abnormal hemoglobin level is not a diagnosis for any of these diseases. Instead, your hemoglobin level will be evaluated based on your symptoms, other blood counts and other test results to diagnose the underlying cause of a high or low hemoglobin level.
Are blood test for hemoglobin results accurate?
The blood test for hemoglobin is one of the most basic blood tests performed during a medical evaluation. The test is commonly used and relied upon in a variety of health care settings.
However, no test is perfect, and your hemoglobin results may be affected by something that does not necessarily indicate a health problem. For example, the results of people who are pregnant, dehydrated and living at high altitudes may not accurately reflect healthy hemoglobin levels.
What do blood test for hemoglobin results mean?
There are many reasons why your hemoglobin level may not be in the normal range.
Low hemoglobin levels may be a sign of the following:
- Different types of anemia
- Thalassemia
- Iron deficiency
- Liver disease
- Cancer and other diseases
- High hemoglobin levels may be a sign of the following diseases
- Lung diseases
- Heart disease
- Polycythemia vera, a condition in which the body makes too many red blood cells. It can cause headaches, fatigue and shortness of breath.
If any of your indicators are abnormal, it doesn't always mean you have a condition that needs to be treated. Diet, activity levels, medications, menstrual periods and other factors can all affect the results. If you live at high altitude, your hemoglobin level may also be higher than normal.
Is there anything else I need to know about blood test for hemoglobin?
Some forms of anemia are mild, while other types of anemia can be serious and even life-threatening if left untreated. If you are diagnosed with anemia, be sure to talk to your health care provider to find out the best treatment option for you.
References:
1. Hemoglobin test - Mayo Clinic
2. Hemoglobin Test: MedlinePlus Medical Test
See also:
2. What Is Blood Test For Iron Called?
3. 2022 Best Home Hemoglobin Meter Buyers Guide
4. Can I take anemia tests at home?
5. How to choose the at-home kidney test？
6. What main factors influence the hemoglobin test for results?