Or perhaps you noticed the red blood cell count flagged as “low” in the bloodwork report? Or noticed “low hemoglobin” in a doctor’s report?
Anemia means having a red blood cell count that is lower than normal, and it’s very common in older adults. About 10% of independently living people over age 65 have anemia. And anemia becomes even more common as people get older.
But many older adults and families hardly understand anemia.
This isn’t surprising: anemia is associated with a dizzying array of underlying health conditions, and can represent anything from a life-threatening emergency to a mild chronic problem that barely makes the primary care doctor blink.
Still, it worries me that older adults and families don’t know more about anemia. If you or your relative has this condition, it’s important to understand what’s going on and what the follow-up plan is. (I’ve so often discovered that a patient didn’t know he or she had had anemia!) Misunderstanding anemia can also lead to unnecessary worrying, or perhaps even inappropriate treatment with iron supplements.
And since anemia is often caused by some other problem in the body, not understanding anemia often means that people don’t understand something else that is important regarding their health.
Fortunately, you don’t have to be a doctor to have a decent understanding of the basics of anemia.
This post will help you understand:
- How anemia is detected and diagnosed in aging adults.
- Symptoms of anemia.
- The most common causes of anemia, and tests often used to check for them.
- What to ask the doctor.
- How to get better follow-up, if you or your relative is diagnosed with anemia.
Defining and detecting anemia
Anemia means having a lower-than-normal count of red blood cells circulating in the blood.
Red blood cells are always counted as part of a “Complete Blood Count” (CBC) test, which is a very commonly ordered blood test.
A CBC test usually includes the following results:
- White blood cell count (WBCs): the number of white blood cells per microliter of blood
- Red blood cell count (RBCs): the number of red blood cells per microliter of blood
- Hemoglobin (Hgb): how many grams of this oxygen-carrying protein per deciliter of blood
- Hematocrit (Hct): the fraction of blood that is made up of red blood cells
- Mean corpuscular volume (MCV): the average size of red blood cells
- Platelet count (Plts): how many platelets (a smaller cell involved in clotting blood) per microliter of blood
(For more information on the CBC test, see this Medline page. For more on common blood tests, see Understanding Laboratory Tests: 10 Commonly Used Blood Tests for Older Adults.)
By convention, to detect anemia clinicians rely on the hemoglobin level and the hematocrit, rather than on the red blood cell count.
A “normal” level of hemoglobin is usually in the range of 14-17gm/dL for men, and 12-15gm/dL for women. However, different laboratories may define the normal range slightly differently.
A low hemoglobin level — meaning, it’s below normal — can be used to detect anemia. Clinicians often confirm the lower hemoglobin level by repeating the CBC test.
If clinicians detect anemia, they usually will review the mean corpuscular volume measurement (included in the CBC) to see if the red cells are smaller or bigger than normal. We do this because the size of the red blood cells can help point doctors towards the underlying cause of anemia.
Hence anemia is often described as:
- Microcytic: red cells smaller than normal
- Normocytic: red cells of a normal size
- Macrocytic: red cells larger than normal
Symptoms of anemia
The red blood cells in your blood use hemoglobin to carry oxygen from your lungs to every cell in your body. So when a person doesn’t have enough properly functioning red blood cells, the body begins to experience symptoms related to not having enough oxygen.
Common symptoms of anemia are:
- shortness of breath
- high heartrate
- becoming paler, which is often first seen by checking inside the lower lids
- lower blood pressure (especially if the anemia is caused by bleeding)
However, it’s very common for people to have mild anemia — meaning a hemoglobin level that’s not way below normal — and in this case, symptoms may be barely noticeable or non-existent.
That’s because the severity of symptoms depends on two crucial factors:
- How far below normal is the hemoglobin level?
- How quickly did the hemoglobin drop to this level?
This second factor is very important to keep in mind. The human body does somewhat adapt to lower hemoglobin levels, but only if it’s given weeks or months to do so.
So this means that if someone’s hemoglobin drops from 12.5gm/dL to 10gm/dL (which we’d generally consider a moderate level of anemia), they are likely to feel pretty crummy if this drop happened over two days, but much less so if it developed slowly over two months.
People sometimes want to know how low the hemoglobin has to be for anemia to be “severe.” This really depends on the past medical history of the person and on how fast the hemoglobin dropped, but generally, a hemoglobin of 6.5 to 7.9 gm/dL is often considered “severe” anemia.
People also sometimes want to know how low can hemoglobin go before causing death. In general, a hemoglobin less than 6.5 gm/dL is considered life-threatening. But again, how long the body can tolerate a low hemoglobin depends on many factors, and including whether the hemoglobin is continuing to drop quickly (due an internal bleed, for instance) or is slowly drifting down. A study of Jehovah’s Witnesses who died after refusing transfusions found that those with hemoglobins between 4.1 to 5 gm/dL died, on average, about 11 days later.
The most common causes of anemia in aging adults
Whenever anemia is detected, it’s essential to figure out what is causing the low red blood cell count.
Compared to most cells in the body, normal red blood cells have a short lifespan: about 100-120 days. So a healthy body must always be producing red blood cells. This is done in the bone marrow and takes about seven days, then the new red blood cells work in the blood for 3-4 months. Once the red blood cell dies, the body recovers the iron and reuses it to create new red blood cells.
Anemia happens when something goes wrong with these normal processes. In kids and younger adults, there is usually one cause for anemia. But in older adults, it’s quite common for there to be several co-existing causes of anemia.
A useful way to think about anemia is by considering two categories of causes:
- A problem producing the red blood cells, and/or
- A problem losing red blood cells
Here are the most common causes of low hemoglobin for each category:
Problems producing red blood cells. These includes problems related to the bone marrow (where red blood cells are made) and deficiencies in vitamins and other substances used to make red blood cells. Common specific causes include:
- Chemotherapy or other medications affecting the bone marrow cells responsible for making red blood cells.
- Iron deficiency. This occasionally happens to vegetarians and others who don’t eat much meat. But it’s more commonly due to chronic blood loss, such as heavy periods in younger women, or a slowly bleeding ulcer in the stomach or small intestine, or even a chronic bleeding spot in the colon.
- Lack of vitamins needed for red blood cells. Vitamin B12 and folate are both essential to red blood cell formation.
- Low levels of erythropoietin. Erythropoietin is usually produced by the kidneys, and helps stimulate the bone marrow to make red blood cells. (This is the “epo” substance used in “blood doping” by unethical athletes.) People with kidney disease often have low levels of erythropoietin, which can cause a related anemia.
- Chronic inflammation. Many chronic illnesses are associated with a low or moderate level of chronic inflammation. Cancers and chronic infections can also cause inflammation. Inflammation seems to interfere with making red blood cells, a phenomenon known as “anemia of chronic disease.”
- Bone marrow disorders. Any disorder affecting the bone marrow or blood cells can interfere with red blood cell production and hence cause anemia.
Problems losing red blood cells. Blood loss causes anemia because red blood cells are leaving the blood stream. This can happen quickly and obviously, but also can happen slowly and subtly. Slow bleeds can worsen anemia by causing an iron-deficiency, as noted above. Some examples of how people lose blood include:
- Injury and trauma. This can cause visibly obvious bleeding, but also sometimes causes people to bleed into a space inside the body, which can be harder to detect.
- Chronic bleeding in the stomach, small intestine, or large bowel. This can be due to many reasons, some common ones include:
- taking a daily aspirin or non-steroidal anti-inflammatory drug
- peptic ulcer disease
- cancer in the stomach or bowel
- Frequent blood draws. This is mainly a problem for people who are hospitalized and getting daily blood draws.
- Menstrual bleeding. This is usually an issue for younger women but occasionally affects older women.
There is also a third category of anemias, related to red blood cells being abnormally destroyed in the body before they live their usual lifespan. These are called hemolytic anemias and they are much less common.
A major study of causes of anemia in non-institutionalized older Americans found the following:
- One-third of the anemias were due to deficiency of iron, vitamin B12, and/or folate.
- One-third were due to chronic kidney disease or anemia of chronic disease.
- One-third of the anemias were “unexplained.”
How doctors evaluate anemia
Once anemia is detected, it’s important for health professionals to do some additional evaluation and follow-up, to figure out what might be causing the anemia.
Understanding the timeline of the anemia — did it come on quickly or slowly? Is the red blood count stable or still trending down with time? — helps doctors figure out what’s going on, and how urgent the situation is.
Common follow-up tests include:
- Checking the stool for signs of microscopic blood loss
- Checking a ferritin level (which reflects iron stores in the body)
- Checking vitamin B12 and folate levels
- Checking kidney function, which is initially done by reviewing the estimated glomerular filtration rate (included in most basic bloodwork results)
- Checking the reticulocyte count, which reflects whether the bone marrow trying to produce extra red blood cells to compensate for anemia
- Checking levels of an “inflammation marker” in the blood, such as the erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP)
- Evaluation of the peripheral smear, which means the cells in the blood are examined via microscope
- Urine tests, to check for proteins associated with certain blood cell disorders
If the anemia is bad enough, or if the person is suffering significant symptoms, doctors might also consider a blood transfusion. However, although even mild anemia has been associated with worse health outcomes, research suggests that transfusing mild to moderate anemia generally isn’t beneficial. (This issue especially comes up when people are hospitalized or acutely ill.)
What to ask the doctor about anemia
If you are told that you or your older relative has anemia, be sure you understand how severe it seems to be, and what the doctors think might be causing it. This will help you understand the plan for follow-up and treatment.
Some specific questions that can be handy include:
- How bad is this anemia? Does it seem to be mild, moderate, or severe?
- What do you think is causing it? Could there be multiple causes or factors involved?
- How long do you think I’ve had this anemia? Does it seem to be stable or is it getting worse?
- Is this the cause of my symptoms or do you think something else is causing my symptoms?
- Could any of my medications be involved?
- What is our plan for further evaluation?
- What is our plan for treating this anemia?
- When do you recommend we check the CBC again? What is our plan for monitoring the anemia?
Be sure to request and keep copies of your lab results. It will help you and your doctors in the future to be able to review your past labs related to anemia and any related testing.
Avoiding common pitfalls related to anemia and iron
A very common diagnosis in older adults is iron-deficiency anemia. If you are diagnosed with this type of anemia, be sure the doctors have checked a ferritin level or otherwise confirmed you are low on iron.
I have actually reviewed medical charts in which a patient was prescribed iron for anemia, but no actual low iron level was documented. This suggests that the clinician may have presumed the anemia was due to low iron.
However, although iron deficiency is common, it’s important that clinicians and patients confirm this is the cause, before moving on to treatment with iron supplements. Doctors should also assess for other causes of anemia, since it’s very common for older adults to simultaneously experience multiple causes of anemia (e.g. iron deficiency and vitamin B12 deficiency).
If an iron deficiency is confirmed, be sure the doctors have tried to check for any causes of slow blood loss.
It is common for older adults to develop microscopic bleeds in their stomach or colon, especially if they take a daily aspirin or a non-steroidal anti-inflammatory drug (NSAIDs) such as ibuprofen. (For this reason — and others — NSAIDs are on the Beer’s list of medications that older adults should use with caution.)
Bear in mind that iron supplements are often quite constipating for older adults. So you only want to take them if an iron-deficiency anemia has been confirmed, and you want to make sure any causes of ongoing blood loss (which causes iron loss) have been addressed.
The most important take home points on anemia in older adults
Here’s what I hope you’ll take away from this article:
1.Anemia is a very common condition for older adults, and often has multiple underlying causes.
2. Anemia is often mild-to-moderate and chronic; don’t let the follow-up fall through the cracks.
3. If you are diagnosed with anemia or if you notice a lower than normal hemoglobin on your lab report, be sure to ask questions to understand your anemia. You’ll want to know:
- Is the anemia chronic or new?
- Is it mild, moderate, or severe?
- What is thought to be the cause? Have you been checked for common problems such as low iron or low vitamin B12?
4. If you are diagnosed with low iron levels: could it be from a small internal bleed and could that be associated with aspirin, a non-steroidal anti-inflammatory medication such as ibuprofen, or another medication?
5. Keep copies of your lab reports.
6. Make sure you know what the plan is, for following your blood count and for evaluating the cause of your anemia.
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You may also find it helpful to read these related articles:
Understanding Laboratory Tests: 10 Commonly Used Blood Tests for Older Adults
How to Avoid Harm from Vitamin B12 Deficiency
This article was first published in 2016 & minor updates were made in Jan 2023. (The fundamentals of anemia in older adults don’t change much over time.)