Is My Dog Anemic? — Checking Iron Levels with Ferritin and Transferrin

ImmunityQ&AMeongsiljang Veterinary Advisory Board

Ferritin and transferrin are key blood test markers used to diagnose anemia and assess iron status in pets. Interpreting these two values together is essential for pinpointing the exact cause.

What Are Ferritin and Transferrin Tests?

An illustration showing the roles of ferritin and transferrin in pets' blood

Ferritin and transferrin are blood test markers used to assess iron status in pets. The key is to evaluate both values together. Ferritin reflects the amount of iron stored in cells, while transferrin indicates the level of the protein responsible for transporting iron in the blood. When a complete blood count (CBC) alone is insufficient, these two markers help accurately distinguish between iron deficiency and chronic inflammation.

Why Should Both Be Evaluated Together?

Ferritin is the "storage warehouse" for iron, while transferrin acts as the "delivery courier." When iron levels are low, the warehouse (ferritin) empties out, and the courier (transferrin) circulates more actively in an attempt to capture available iron. Conversely, in cases of chronic inflammation, the body sequesters iron, causing ferritin levels to rise instead. Relying on a single value can lead to misdiagnosis, which is why veterinary internal medicine textbooks emphasize interpreting both markers together.

Changes in Ferritin and Transferrin Levels by Situation

Item	Iron deficiency anemia	Chronic inflammation/infection	Hemolytic anemia	Iron overload
Ferritin	Low ↓	High ↑	Normal to high	Very high ↑↑
Transferrin	High ↑	Low ↓	Normal	Normal to high
Serum iron	Low ↓	Low ↓	Normal to high	High ↑
Main causes	Hemorrhage, nutritional deficiency	Tumor, inflammatory disease	Immune-mediated destruction	Excessive transfusion

Actual interpretation must always be done with a veterinarian.

When Should Testing Be Performed?

Here are the signs you can notice at home: - Gum color changes: If the gums are pale white or yellow instead of pink, anemia may be suspected. - Easy fatigue: The pet may walk shorter distances than usual and breathe heavily. - Decreased appetite: The pet may eat less or show unusual behaviors like licking dirt or walls. - Black stool or blood in urine: These are signs of chronic bleeding, indicating iron loss. - Coexisting chronic conditions: If there are chronic diseases such as tumors or inflammatory conditions, the body may retain iron, leading to "anemia of chronic disease." In such cases, it’s important to check iron markers like ferritin and transferrin.

A veterinarian checks a puppy's gum color to assess for anemia.

Seek Immediate Veterinary Care in These Cases

If your pet’s gums turn pale, their breathing becomes rapid, or you notice black, tarry stools, there may be internal bleeding. In such cases, do not wait for ferritin test results—seek emergency veterinary care immediately. Cats, in particular, often deteriorate quietly without obvious signs of anemia, so if you suddenly notice a sharp drop in activity level, take them to the vet right away.

How Is the Test Performed?

Testing for ferritin and transferrin requires only a small blood sample, similar to a routine blood test. Typically, about 2–3 mL is drawn from a vein in the front leg or neck. Fasting is often required, so be sure to confirm this with your veterinarian before your visit. Results may be available the same day if analyzed in-house, or within 2–3 days if sent to an external laboratory. For accurate interpretation, these results should be evaluated alongside complete blood count (CBC), serum iron, and total iron-binding capacity (TIBC) values. You can find more detailed information on symptoms and causes of anemia in dogs.

A dog having a blood test at the veterinary clinic

What to Do If Results Are Abnormal?

We don’t immediately prescribe medication just because a value falls outside the normal range. The first step is always to identify the underlying cause. - Low ferritin: We first check for sources of bleeding (via gastrointestinal endoscopy or ultrasound). - High ferritin: We look for inflammatory causes such as tumors, infections, or liver disease. - Abnormal transferrin: We add tests to assess nutritional status and liver function. Your veterinarian will then develop a treatment plan and nutritional supplementation strategy tailored to your pet’s weight and underlying condition.

Do Not Administer Iron Supplements Without Veterinary Guidance

Giving your pet human iron supplements or multivitamins without veterinary guidance can be dangerous. Pets are particularly sensitive to iron overload, which can cause vomiting, diarrhea, and liver toxicity. Iron poisoning can simultaneously affect multiple organ systems, including the gastrointestinal, hepatic, cardiovascular, and nervous systems, leading to rapid deterioration of symptoms. Even if ferritin levels are low, it is safest to have a veterinarian identify the underlying cause before prescribing a pet-specific iron supplement.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

How often should I get a ferritin test?

Healthy pets don’t need regular testing. If anemia is suspected or if your pet is being managed for a chronic condition (such as kidney disease or cancer), follow-up tests are typically recommended every 3 to 6 months, as determined by your veterinarian.

Are the normal reference ranges the same for dogs and cats?

It varies. Reference ranges differ depending on species, breed, age, and sex, and criteria can also vary slightly between laboratories and their equipment. For the most accurate interpretation, review the normal range listed on your results sheet with your veterinarian.

Can ferritin levels be raised through diet alone?

If the deficiency is mild and the underlying cause has been resolved, you can supplement with iron-rich foods such as liver, beef, and leafy green vegetables. However, for moderate to severe deficiencies, dietary changes alone are insufficient, and prescription medication is essential.

How much does the examination cost?

Costs vary from clinic to clinic, so it’s hard to give you an exact figure. Most clinics bundle iron-related tests with a complete blood count (CBC), so I’d recommend calling your vet directly before your visit to get a precise quote.

Is it more difficult to examine cats?

Cats can experience temporary fluctuations in their test results due to stress, so it’s important to draw blood in a calm environment. Transporting your cat to the clinic slowly in a carrier and allowing time for them to adjust to new smells can improve the accuracy of the results.

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References

[1] Ettinger SJ, Feldman EC, Cote E. Textbook of Veterinary Internal Medicine, 8th Ed. Elsevier, 2017.

[2] Weiss DJ, Wardrop KJ. Schalm's Veterinary Hematology, 6th Ed. Wiley-Blackwell, 2010.

[3] Naigamwalla DZ et al., Iron deficiency anemia, Canadian Veterinary Journal, 2012.