FrançaisWhat anemia means on a blood count
Anemia is defined as a decreased hematocrit or hemoglobin [1]. The hematocrit (HCT) is calculated by the analyser; the packed cell volume (PCV), measured by spinning a small tube of blood, is used as an equivalent in practice [1]. The red cell count (RBC) usually falls with them.
Two situations can make a dog look anemic without true anemia: sedation or anaesthesia, which can temporarily store up to 30% of red cells in the spleen, and young age, as puppies under about 4 months have a physiologic anemia while they grow [1]. Conversely, sighthounds such as Greyhounds normally have a higher hematocrit, so a value that looks normal can be low for them [2].
How to read the hematocrit line
Here is an example line from the red cell block of the CBC.
- Abbreviation HCT or PCV: the share of the blood volume made of red cells.
- Result 27% in this illustrative line.
- Unit %; some laboratories write L/L (0.27 L/L = 27%).
- Laboratory interval The example uses the dog interval of the Merck Veterinary Manual [3]; laboratories differ.
- Flag L: below the interval. Cornell’s guidelines would call 20–30% a moderate anemia in a dog [1].
How severe is it?
| Grade (dogs) | Hematocrit | What it usually means for the dog |
|---|---|---|
| Reference interval at Cornell | 41–58% | Not anemic [1]. |
| Mild | 30–40% | Often no visible signs; the cause still matters. |
| Moderate | 20–30% | Tiredness and pale gums become more likely. |
| Severe | Below 20% | Needs prompt veterinary care. |
Regenerative or not: the reticulocyte count
Reticulocytes are young red cells just released by the bone marrow. A high count shows the marrow is replacing lost cells: the anemia is regenerative, which points to blood loss or red cell destruction (hemolysis). A low count points to reduced production [1].
Timing matters: the bone marrow needs 3 to 5 days to respond, so an anemia that started suddenly can look non-regenerative at first and show reticulocytes a few days later [1].
| Absolute reticulocytes (dogs) | Degree of regeneration [4] |
|---|---|
| Below about 92,000/µL | Inadequate or no regeneration |
| About 93,000–153,000/µL | Equivocal |
| About 154,000–200,000/µL | Mild |
| Above about 200,000/µL | Moderate to marked |
The absolute count is calculated as the reticulocyte percentage × the red cell count, which many analysers report directly [4].
The main families of causes
- Blood loss. Injury, bleeding disorders such as low platelets, or chronic loss from the gut or heavy parasite burdens, which can end in iron deficiency with small, pale red cells [5].
- Red cell destruction (hemolysis). Immune-mediated hemolytic anemia (IMHA) is an important cause in dogs; the ACVIM consensus recommends screening for triggers such as infections, cancer and drugs [6]. Toxins such as onions or garlic and zinc (swallowed coins) can also destroy red cells [5].
- Reduced production. Inflammation and chronic disease commonly cause a mild to moderate non-regenerative anemia; diseases of the bone marrow are less common [1, 5].
The values often read with anemia
En français : l’anémie chez le chien et le chat.
When the immune system destroys the red cells, see IMHA in dogs.
Questions to ask your veterinarian
- How severe is the anemia, and how fast has it developed compared with previous tests?
- Is it regenerative? What is the absolute reticulocyte count?
- Was a blood smear examined, and what did it show about the red cells?
- Which causes do you want to rule out first, and with which tests?
- Which signs at home should make me call you straight away?
Get your dog’s full blood count explained, line by line.
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Frequently asked questions
What is the difference between regenerative and non-regenerative anemia?
In a regenerative anemia, the bone marrow releases many young red cells (reticulocytes) to replace cells lost through bleeding or destruction. In a non-regenerative anemia, the marrow is not producing enough, as often happens with chronic inflammation or disease [1].
What are the symptoms of anemia in dogs?
Pale gums, tiredness, reluctance to exercise, fast breathing and a fast heart rate. With red cell destruction, the gums or eyes can turn yellow. Mild anemia often causes no visible signs.
What is a red flag for anemia in a dog?
Very pale or yellow gums, collapse, breathing difficulty, red or brown urine, or any bleeding. These need urgent veterinary care.
What is the best medicine for anemia in dogs?
There is no single medicine: treatment depends on the cause, from stopping a blood loss to treating an immune or infectious disease. Do not give iron or other supplements without your vet’s advice.
Can puppies have a low hematocrit?
Yes. Puppies under about 4 months often have a physiologic anemia linked to rapid growth, so their results are read with age-adapted expectations [1].
Sources
- eClinPath, Cornell University College of Veterinary Medicine. Anemia: overview. eclinpath.com/hematology/anemia
- eClinPath, Cornell University College of Veterinary Medicine. Assessment of regeneration. eclinpath.com/hematology/anemia/assessment-regeneration
- Merck Veterinary Manual. Hematology (complete blood count) reference ranges. merckvetmanual.com/reference-values-and-conversion-tables/reference-guides/hematology-reference-ranges
- eClinPath, Cornell University College of Veterinary Medicine. Absolute reticulocyte count. eclinpath.com/hematology/tests/absolute-reticulocyte-count
- eClinPath, Cornell University College of Veterinary Medicine. Anemia summary: mechanisms and causes. eclinpath.com/hematology/anemia/cause-of-anemia-summary
- Garden OA et al. ACVIM consensus statement on the diagnosis of immune-mediated hemolytic anemia in dogs and cats. J Vet Intern Med. 2019;33(2):313-334. doi.org/10.1111/jvim.15441
Laboratory methods and reference intervals vary. This article explains; it does not diagnose. For a decision about your pet, use the original report and talk to your veterinarian. Our editorial policy.