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What is Bone Marrow Biopsy?

The bone marrow is responsible for producing cell lines vital to life including red blood cells, white cells, and platelets. Conditions resulting in severe anemia (lack of red blood cells), or abnormal white cell or platelet readings may need a bone marrow biopsy in order to identify the root cause. Biopsy is a diagnostic tool which enables the clinician to reach a diagnosis and start appropriate treatment. 

Bone marrow biopsy may be undertaken in first opinion practice, when the clinician feels confident to do so, or at a referral center. The procedure can often be undertaken under sedation and local anesthetic, with the patient feeling no more than a momentary discomfort.

Bone Marrow Biopsy Procedure in Cats

The patient will already have had diagnostic tests such as blood samples and an analysis of fresh blood smears. It is entirely appropriate to first screen the cat for problems outside of the bone marrow which can affect cell line production. Thus ultrasound or radiographic imaging of the chest and abdomen may have already been performed and found normal. 

There are three locations to choose from to harvest the sample. The cat is sedated and the fur clipped over one of the collection sites:

  1. The wing of the ilium on the pelvis
  2. The greater trochanter of the femur (thigh bone)
  3. The proximal humerus 

Local anesthetic is injected into the skin and the membrane (periosteum) overlying the bone. A scalpel is used to make a small stab incision in the skin. A bone marrow biopsy needle is placed on a bony landmark and, with a twisting pushing motion, pushed through the bone into the marrow. 

Different techniques are used depending on the type of biopsy needle used. One method involves collecting a 'plug' of marrow in the needle, which is then withdrawn and the plug spread over a microscope slide. Alternatively, a small volume of fluid is injected into the marrow cavity and the resulting mix sucked back into a syringe, and then smeared on a slide. 

The biopsy tool is removed from the site and a single suture placed over the stab incision. The slides are sent to a laboratory where a histologist examines the types of cells present. 

Efficacy of Bone Marrow Biopsy in Cats

Bone marrow biopsy is a diagnostic tool used to identify the nature of the underlying bone marrow problem. It is not a treatment in itself, but a means to give the clinician the information necessary to decide on a course of treatment. 

The information gained by examining the bone marrow cannot be obtained in other ways. In those cases where a bone marrow biopsy is indicated, the only options are to either perform a bone marrow biopsy or go without the information it would give. 

It should be said that bone marrow biopsy is a targeted test, which is only performed when the results of other investigations point strongly to bone marrow disease. 

Bone Marrow Biopsy Recovery in Cats

The collection of bone marrow is considered a minor procedure and in good natured cats is often performed under sedation and local anesthetic. This means there is relatively little for the cat to recover from, except to fully wake from the sedation. The single suture placed in the skin is usually removed after 10 to 14 days. 

Once harvested, the sample is sent away and the results may not be known for several days. This means that targeted treatment may not start immediately, but is held pending the histology results. 

Cost of Bone Marrow Biopsy in Cats

The typical cost of a bone marrow biopsy or aspirate, including sedation, taking the sample, and submitting it to a histologist is around $500.

Cat Bone Marrow Biopsy Considerations

Bone marrow biopsy is a relatively low risk procedure. It is not usually associated with a high degree of hemorrhage, so unless the patient is known to have a bleeding disorder, then it is considered relatively complication free. 

The biggest factor to consider is that diagnostic samples are not always obtained. This can be down to the nature of the bone marrow disease or the sampling technique. For example, some types of bone marrow fibrosis (where active marrow is replaced by inactive scar tissue) exfoliates cells poorly, which means that cells do not yield up to the sampling. Alternatively hemodilution can occur, where blood accidentally contaminates the sample and makes it harder to interpret. 

The chances of using a negative sample can be reduced by staining the slide in-house, and checking for good cellularity before submitting it to the histologist. This then offers the opportunity to take a second sample should the first one be inadequate. 

Bone Marrow Biopsy Prevention in Cats

With the exception of bone marrow suppression as a result of exogenous estrogen administration, the majority of causes of bone marrow suppression are not predictable or preventable. 

Bone Marrow Biopsy Questions and Advice from Veterinary Professionals

domestic medium hair
3 Years
Serious condition
0 found helpful
Serious condition

Has Symptoms

oral bleeding
lesion on roof of mouth

Our 3 year old boy has recently started bleeding from his mouth after eating dry food. We took him in to get examined and they noticed a dark patch/lesion in the roof of his mouth as well as his ridges missing on the same half. The lesion is not a growth - it almost looks like a small patch of his mouth is missing. They ran bloodwork and found he was anemic. They say they have no clue what is wrong with him and are running a bone marrow test today to determine why he's anemic and if it's related to the lesion. We are very concerned.

As a side note- he has never been able to hiss. He only huffs out air as he tries to when he's wrestling with our other cat. We've never witnessed him hissing. Not sure if this is related.

He is otherwise in great health, very playful, very snuggly and shows no sign of discomfort or lethargy.

Is there any idea what could be going on with him? We love him dearly but are afraid we're getting sucks dry for money if they still can't find out what's wrong.

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Domestic -part Siamese, part Ragdoll
4 Years
Critical condition
1 found helpful
Critical condition

Has Symptoms

Very low red blood cell count
Non-regenerative anaemia
Bacterial UTI

Morphs, a healthy up to now cat, was showing peeing out of the litter box behavior and at some point showed started losing significant amounts of blood in his urine. He was checked for urinary crystals and was found negative, he was taking some soft antibiotics. Then he got tachypnea, lethargy (coming and going, according to the RBC "loss") and a 6% drop in HCT within a week, as he was undergoing various tests for infectious diseases. His HCT stabilized for 5 days at 10%, a point where he got a blood transfusion (+3%). The blood in the pee has continued all this time, his urine culture showed a nasty bacterial infection resistant to a lot of antibiotics, so he started being treated for that and he also gets cortisone. Because he showed kidney damage/inflammation (which could have been chronic), he was also erythropoietin injected, showing very little response to that so far. His HCT after 6 days of blood transfusion fell back to 10%. Would all that be a strong indication towards a bone marrow biopsy?

Dr. Michele King, DVM
Dr. Michele King, DVM
1611 Recommendations
If Morphs truly has a non-regenerative anemia supported by a reticulocyte count, then a bone marrow biopsy would be the next logical test, yes. I hope that all goes well for him!

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6 Years
Serious condition
0 found helpful
Serious condition

Has Symptoms

Hair Loss
Increased Appetite
Urinating Outside Litterbox
Excessive drinking
Bald spots
open sores
Weight loss,
Constant howling and screaming
excessive urine output

I am trying to determine possible diagnoses for my cat, he lost a bunch of weight and muscle mass after i moved last year, he is still food obsessed and drinks A LOT of water but has started peeing outside the litter box. He pees excessively now. He pees all over the floor or in any food dish i give him. He already had skin and allergy issues causing him to lick bald spots but now he has more than ever. He had a seizure when he was a kitten and was oxygen deprived and has had cognitive issues since then. He yells and meows ALL THE TIME. He steals food, including eating an entire unopened stick of butter than he then practically inhaled. The vet thought it was a viral infection or bone cancer based on his blood work a few months ago but after taking the medicine for a viral infection he hasn't gotten any better. I have him on some steroids for potential bone cancer but he has gotten a lot worse, lost more weight and now has more open sores between his mouth and nose.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3320 Recommendations
There are many possible causes for the symptoms presented with which may include infection, hormonal conditions, cancer, autoimmune diseases, kidney failure (would have been easily flagged on blood tests) among other causes; it can be difficult to narrow in on a diagnosis, I cannot think of a specific cause based on the information presented in the question. If your Veterinarian is able to narrow in on a specific cause, it may be worth visiting a Specialist. Regards Dr Callum Turner DVM

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15 Years
Moderate condition
0 found helpful
Moderate condition

Has Symptoms


Pedro has never been sick. 5 weeks ago he had an abscessed anal gland that he went to the ER for. It healed nice and fast. Since that time, he has not been the same cat. He stays behind the couch 24/7 except when he comes out to eat. Went to the vet 2 weeks later, couldn't find anything wrong. Continued to isolate himself from me and his brother. Went to a different vet today where they did full exam and blood work. Outwardly could, again, find nothing wrong. Seems healthy. Labwork showed low WBC, HGB, HCT, and platelets. His metabolic profile was all WNL. Before today, his last labs were just done 9/2017 and his WBC were slightly low (4.64) at that time. Everything else was ok. Vet didnt think it was cause for concern at that time. Today's vet was a little concerned but they do not offer bone marrow biopsy here. Could this be anything other than a bone marrow malignancy of some kind? I don't know what to do. She mentioned "erlichia" but that sounds pretty uncommon, especially in an indoor cat. Your thoughts?

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3320 Recommendations
It does sound like either there is a reduction in blood cell production (bone marrow issue, kidney or liver issue) or an increase in destruction (infections, autoimmune disease etc…), a bone marrow aspirate would help in this instance to determine whether there are any abnormalities or anything else to note. You should consider asking your Veterinarian if they can recommend somewhere where a bone marrow biopsy can be performed. Regards Dr Callum Turner DVM

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Domestic Longhair
14 Years
Has Symptoms
My adult DLH is named Smithers. Smithers is 14. We have found out that he has IMHA and IBD. We tested for Leukemia etc and all was negative. Vitamin B12 was low so we started on shots, and Prednisolone for the IMHA. Smithers is moaning. Smithers had a transfusion be of the IMHA and non-regeneration. He then had the bone biopsy. I am awaiting results and fear it won't be good at all.