This is important because no test is every 100% accurate.

Cushings Disease Tests

Cushing’s Syndrome is a disease of excessive cortisol production. The ACTH Stimulation Test (AST) measures how high the cortisol goes after an injection of ACTH. The Low Dose Dexamethasone Suppression Test (LDDST) measures how low the cortisol goes after a dexamethasone dose.

Neither test is especially accurate. ASTs are believed to have a false positive rate of 5-10% and a false negative rate of 20%. The LDDST is much the same in reverse. Therefore, if you screen the general dog population, where Cushing’s disease sits at around 0.3%, most of the positive results will be false positives.

If this seems crazy, check out this longer post on false positives.

This is where an online tool can help.

A Diagnostic Tool For Cushings

Recent analysis of large numbers of dogs with and without Cushing’s disease has shown that there are certain features that can be used to make a prediction. This is important for four reasons:

1. A high probability suggests that testing, though expensive, is worth doing
2. A low probability with a positive test should make you suspicious of a false positive
3. A high probability with a negative test should make you suspicious of a false negative
4. A probability that matches the test result helps improve confidence in starting treatment

To use this tool, just enter a score for each line, then subtract or add each number to get the actual score. It will work better if you’ve already had some basic blood and urine tests done.

Now look up the percent chance that your dog has Cushing’s Disease in the following table.

Hopefully the answer will help you decide what to do next, especially if your funds aren’t limitless. Remember: these are just probabilities, and must be confirmed with specific testing by your veterinarian.

Now Read: Treatment Of Cushing’s Disease

Schofield, I,  Brodbelt, DC,  Niessen, SJM, et al.  Development and internal validation of a prediction tool to aid the diagnosis of Cushing’s syndrome in dogs attending primary‐care practice. J Vet Intern Med.  2020; 34: 2306– 2318. https://doi.org/10.1111/jvim.15851

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

If you understand why that is you will be much better equipped to talk to your vet about any tests on your pet.

What Is A False Positive?

A false positive is simply a test result that wrongly states that something is present when in fact it is absent.

False positives are usually the major achilles heel of any diagnostic test. Without resorting to any jargon, I think I can explain why.

Why False Positives Happen

Every test has a sensitivity and specificity, which measure the test’s inbuilt error rate.

Even if used correctly, a test with a sensitivity of 90% will miss one in ten positive cases. We call these false negatives. A test with a specificity of 90% will have one in ten false positives. Obviously, the closer both numbers are to 100% the better, but they never are. It’s an imperfect world.

These numbers will worsen if the sample quality is poor, the test is stored incorrectly or there are operator errors.

Now let’s imagine that we have a test for coronavirus that has a specificity of 99.9%. This is better than any test I currently have available.

Say we now want to test:

• one million people
• with the rate of coronavirus at 10 in a million people

So, let’s test!

1. We will find 10 true positive cases
2. We will find 1000 false positive cases

This makes the test 100 times more likely to be wrong than right! How can this be true??

A test with a specificity of 99.9% will be accurate for 999,000 of the cases and inaccurate for the remaining 0.1%, or 1000.

Does This Make Testing Useless?

No, not at all. What you see here is the problem of testing for diseases that are rare in the community. When the rate of true positives is so low, the results are swamped by the false positives that always exist.

But that doesn’t mean we don’t test. It’s what we do next that matters.

What needs to be done is some sort of confirmation. In the famous coronavirus case, there is talk that a second test was negative, and this would have been sufficient warning if true.

The best thing to do is test in a completely different way. Otherwise, the same fault in the first test could happen twice.

Some Vet Testing Examples

At the start is pictured an ELISA test for giardia, coronavirus (a different one!) and parvovirus in dogs. I do this all the time.

If the dog has appropriate symptoms, and there’s a known epidemic, I’ll believe the test. In other words, the rate in the community is high and I’ve got other evidence.

If the dog is not very sick, and I haven’t seen others affected, I’m highly suspicious of a false positive. I’ll definitely retest using a DNA probe called PCR.

Testing for feline leukaemia virus in Australia is another good example. There’s so little of it about that any positive test should be confirmed by another means too.

It’s even true for routine blood testing. With up to 50 individual values being measured, it’s too easy for one of these to be a false positive. Therefore, if it doesn’t seem right, measure it again.

Remember, false positives are mainly a problem when the thing you’re looking for is rare. So don’t fear that testing is useless. It’s almost always spot on. You just need to know how to suspect it when it’s not.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Before we start, it might help to know why a pee sample can be important.

Why Is Urinalysis Needed?

With urine analysis (commonly called urinalysis), you can:

• Diagnose a urinary tract infection
• Separate behavioural from medical causes of urine spraying in cats
• Confirm kidney disease (after blood tests)
• Diagnose a portosystemic shunt
• Diagnose diabetes mellitus
• and so much more

The best container for urine collection is the yellow-top pot you get from your vet. If you don’t have one of these, any glass jar or plastic container will do as long as it’s clean and dry. Just make sure that anything sugary has been completely removed to avoid a false diagnosis of diabetes.

How To Get Urine From A Small Dog

Collecting urine from dogs is easiest on a walk. The best time to try is after a long rest, such as first thing in the morning or when you get home from work. For large dogs, all you have to do is hold the container under the stream. And maybe wear gloves!

Small dogs, especially females, urinate close to the ground and pass it quickly. Most of the time, whenever you try to put a container nearby, they get spooked and stop.

There are three tricks here:

1. Collect the urine in a long flat container without a high lip. A kidney dish works well, but at home you could use the edge of a takeaway plastic container, a saucer or a tray. Once collected, you can pour it into the urine pot.
2. Alternatively, make a handle for the urine pot using an old coat hanger, like in the picture above. Then you don’t need to bend down, and your dog will be less spooked.
3. Be persistent! Even following the points above, your dog will probably keep stopping at first. However, after a while they settle down and decide that despite your weird behaviour, they still need to pee. This usually happens with 24 hours but could take a few weeks in very nervous animals.

How To Get Urine From A Cat

Urine collection from a cat, whether male or female is the same. It absolutely requires that they are already comfortable using a litter box.

1. Empty the litter box, then wash and dry it thoroughly.
2. Fill it with clean, non-absorbent material*
3. Monitor your cat until you see them urinate in the box
4. Pour off the sample into a urine pot

*Suitable nosorb litter includes:

• Thicker plastic shopping bags (e.g. from department or clothing stores) cut into fine strips
• Broken up plastic or styrofoam pieces
• Old Lego®, cleaned and dried first
• Aquarium pebbles
• Commercially available litter replacements such as Kit4Cat & Medicat

Some cats are such creatures of habit that they’ll even go into an empty box. See the help section below if your cat only toilets outside.

How Much Urine Is Needed?

Basic urinalysis can be performed on as little as two mLs of urine (a half teaspoon). That will allow a dipstick reading for blood, pH, protein, glucose, ketones, bilirubin, plus a urine concentration. The cost of this test is listed here.

We prefer you to collect as much as you can to allow for repeat testing, or to submit it to a laboratory.

How Long Is A Sample Good For?

A urine sample should be analysed on the same day it is collected. Excessive storage causes crystals to form and the pH to rise. Therefore, it is best to only attempt to collect it on the days your vet is open. If there is no other choice, an older sample is still better than nothing.

Should I Refrigerate The Urine?

Refrigeration is not advised or necessary for samples kept at room temperature and submitted on the same day they are collected. Like prolonged storage, it causes crystals to form. This can be important if we are looking for the cause of bladder stones in dogs or urinary obstruction in cats.

For other reasons, refrigeration is less of a concern and it will slow down bacterial overgrowth of the sample.

Help! I Can’t Get A Urine Sample

If all else fails, your vet can collect the sample for you. This is either done with a urinary catheter, or via a needle and syringe. The latter technique is essential if infection is suspected and we wish to culture the bacteria for identification.

One option is to make a regular appointment and prevent your pet urinating for 4 hours beforehand so they have a large bladder. Many times, your vet can collect the sample right there and you can take your pet home again.

Other times, we may need to hospitalise your pet while we wait for the bladder to fill. As a last resort, especially in stressed animals, we may recommend a sedation for urine collection.

Regardless of how we do it, urine provides valuable, and often life-changing information. It’s always worth the effort to get!

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Here are just a few reasons why:

• Clinical signs are vague and not specific
• Tests are nowhere near 100% accurate
• There’s a lot of misleading online advice

I spend more time talking dog owners out of a diagnosis of hypothyroidism than I do with any other condition. But I also see genuine cases that need treatment.

The key is to understand how to tell the difference.

Common Signs Of Hypothyroidism

Thyroid hormone is involved in setting the body’s metabolic rate. Therefore, low thyroid levels create symptoms that come on gradually and are hard to recognise. They include one or more of the following:

• Lethargy & reluctance to exercise
• Mental dullness or cold intolerance
• Weight gain
• Dry skin, dandruff or oiliness
• Coarse, brittle, dull or faded hair
• Hair loss, especially on the body like the picture above
• Skin or ear infections
• Skin blackening, especially in the groin and armpits

As you can imagine, with all of this almost any dog could be thought to have a low thyroid level. But on the other hand, an under-active thyroid can easily hide in plain sight. The majority of dogs we diagnose with genuine thyroid disease are brought in for another problem.

Sometimes we first suspect a hormonal disease when the hair doesn’t regrow after it’s clipped. I suspect that this is the origin of the myth about not being able to clip long-haired dogs. Instead of the clipping being the problem, it’s the first step towards a solution.

If hair loss occurs, it’s usually symmetrical and especially in areas of wear like the trunk, thorax or tail, and not the head or legs. Underneath, the skin usually looks normal. However, it’s not a specific sign; the dog above is actually a Boxer with seasonal flank alopecia!

Rare Signs Of Hypothyroidism

Poor fertility is well known with low thyroid levels, but is only rare because very few of these dogs are still being bred.

The most serious and sometimes fatal signs are neurological. They range from wobbly hind legs, weakness or balance problems to myxedema coma at the most extreme. The dog you can see at the top is actually a Labrador. The skin thickening of the face and jowls is caused by myxedema of the skin.

There are three other rare neurologic problems suspected but not proven to be linked to the thyroid. Laryngeal paralysis is a cause of coughing & harsh breathing that worsens with heat or exercise. Megaoesophagus is a swallowing disorder explained here. Myasthenia gravis is one of the causes of muscle weakness. None of these seem to improve when replacement thyroid hormone is given.

Controversial Signs

We’re on even shakier ground with the remaining diseases. These are:

• Dry eye
• Cardiac disease
• Anxiety
• Aggression
• Seizures
• Skin allergy

In each case, there’s no proven link with thyroid disease. However, for all these, it’s still a good idea to take routine blood tests to look for other conditions. Then if there is any concurrent disease (such as thyroid) it can be removed from the picture.

Hypothyroidism is said to be more common in larger breeds in middle age with a slight female bias but no link with desexing. However, I am extremely wary of generalisations given the poor history of correct diagnosis of this condition.

Diagnosis Of Hypothyroidism In Dogs

The most important point is this: many, many dogs have low thyroid levels without having a thyroid problem.

There are three reasons for this:

1. The thyroid level in healthy dogs goes up and down throughout the day
2. Many illnesses suppress the thyroid hormone without it being a separate problem
3. Many drugs interfere with thyroid hormone levels (e.g. steroids, anti-inflammatories, antidepressants, seizure medications)

Having said this, the standard Total T4 test has two advantages: it’s cheap, and very accurate so long as the level is normal. It’s a good screening test as long as you’re prepared for a lot of false positives.

Sometimes, hypothyroid dogs also have mild anaemia and an elevated cholesterol. While not specific, these add a small piece of evidence.

Better diagnosis relies on putting the results a number of tests together with the ‘clinical picture’ of the patient. However, even after this it’s still never possible to be 100% certain. A diagnosis of hypothyroidism is like building up a case from the strands of evidence until we can be beyond reasonable doubt.

So here are a few pathways.

The Path To More Accurate Diagnosis

First, we still start with a Total T4. If it’s normal, you can stop here. That includes breeds like the Akita and Shar Pei that are often said to have occult hypothyroidism. This appears to be a case of over-diagnosis.

If the level is low we first think about how it sits with the dog. If there are no typical signs of thyroid problems, it’s reasonable to stop here as well. If your dog is still energetic, hypothyroidism is extremely unlikely. Very, very few dogs aren’t also showing at least some behavioural signs.

Then we think about drugs or a concurrent illness. You might already know of one, or hints might have appeared in the blood screen. Any possible illness needs to be followed up and treated first, until it’s no longer likely to be affecting the thyroid level. Then test again.

After all this, if your dog has a low T4, appropriate symptoms, and interference from drugs or illness has been minimised, it’s time for more testing.

Advanced Thyroid Tests

There are three common thyroid tests your vet may do, and even more done by veterinary specialists.

The best single test is a Free T4 by equilibrium dialysis. This has accuracy levels of around 90%.

Most vets also request a Thyroid Stimulating Hormone assay at the same time. The combination of an elevated TSH and a low free T4 gives a 98% chance that your dog has hypothyroidism. However, the disadvantage is that these two tests are only positive together for 2 in 3 cases.

In the end, the decision on whether your dog is hypothyroid or not will come down to a value judgement. If enough of the ducks line up, a single result that disagrees may sometimes need to be ignored. When this is the case we proceed to the final test: a therapeutic trial.

Treatment Of Hypothyroidism

Due to the inherent uncertainty of the diagnosis, every dog that starts thyroid hormone is really starting a trial. Hypothyroidism is only confirmed by a favourable response to treatment.

You can expect lethargy and other behavioural changes to improve within a few weeks. Skin and coat changes will take 1 to 2 months to be visible. You should stop the treatment and think again if there are adverse effects like hyperactivity or excessive weight loss, or no response occurs.

Even if caused by the thyroid imbalance, treatment of skin problems like pyoderma or ear infections need to be done separately. You can read more at the links.

After four weeks, your vet will repeat testing either just before a dose to look at the lowest level or 4 to 6 hours after to look at the highest. After that, does are adjusted as needed and you and your dog can start to enjoy the results.

Related: Cushing’s Disease- the other common hormonal problem of dogs

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Image credits at top: Joel Mills [CC BY-SA 3.0], via Wikimedia Commons (left) & self [CC BY-SA 3.0], via Wikimedia Commons (right)

How To Tell If Vomiting Is Abnormal

A ‘normal’ vomit should be quick, happen once only and not be accompanied by a loss of appetite. A good rule of thumb is that if a cat vomits once a week or more, you should get them checked by a vet.

Other important reasons to visit the vet are:

• weight loss
• a poor appetite
• blood in the vomit
• being under one or over ten years old
• having other symptoms such as diarrhoea or lethargy

Causes Of Vomiting In Cats

The causes of vomiting in cats range from simple things like hairballs, food intolerances or eating too fast to serious illnesses like kidney disease and cancer. Your vet should be able to tell if the problem is serious or not.

Hairballs

Hairballs are not as common a cause of vomiting as most cat owners think. Cats swallow hair every time they groom and often carry harmless hairballs in their stomach. Then they vomit, and hey presto: the hairball gets blamed.

Though rare, hairball problems requiring surgery do sometimes occur in long-haired breeds. For short-haired cats, a hairball should only cause a very occasional single vomit. The cat should be otherwise perfectly happy, healthy and have a good appetite.

Read more about the treatment and prevention of hairballs here.

Over-Eating & Rapid Eating

Vomiting is more common when cats are given free access to large meals. It’s just that some cats aren’t very good at eating slowly or stopping at the right time. This is especially true for dry foods, that start to swell once they moisten in the stomach.

Rapid eating is also a problem in cats who feel like they have to compete for food. The result in both cases is usually a firm cylinder of vomited food that doesn’t look like it’s been digested at all. Usually it comes up shortly after eating.

For all cats, stopping dry foods may be needed, but it’s better to use a food dispenser or teach your cat to accept small regular meals. Prevention in multiple cat households should start by allowing them to eat their dinners separately.

Food Intolerances

Just like people, cats can be intolerant of certain foods. Like in the previous example, they should be otherwise normal in health. However, as adverse food reactions are not all that common, it’s important to rule out the more serious reasons for vomiting first.

Once that’s done, you can visit this page on restricted and elimination diets for adverse food reactions.

Gastritis & Gastroenteritis

Cats aren’t as silly as dogs. However, even they will sometimes eat something they shouldn’t. Many of these cats need treatment but should make a full recovery. We almost never identify the cause.

Cats with outside access get more of these stomach upsets, probably due to infections from birds, reptiles or rodents they eat.

Foreign Bodies

Even sillier cats, and especially kittens, sometimes eat foreign material. One cat started vomiting after eating the string that wraps meat, whereas others have eaten cooked bones, fish hooks, toys and even babies’ teats.

The worst cases come from swallowing string, which is why we never advise playing with it. It gets caught on their rough tongue and they seem to almost swallow it by accident.

Worms

Parasites are probably an unusual cause of vomiting, although we can’t be certain. Just to be sure, I always worm cats that vomit frequently.

To illustrate just how vague a symptom it is in cats, vomiting is also one of the signs of feline heartworm. That’s thankfully quite rare these days.

Medications

Nearly all medicines can cause vomiting, so if your cat takes something please make sure you tell your vet.  Particularly common culprits are treatments for feline arthritis and hyperthyroidism.

Viruses

Many viral infections sometimes have vomiting as part of their symptoms. These include feline infectious peritonitis (FIP), feline panleucopaenia (also called feline enteritis or parvovirus) and feline leukaemia virus (FeLV).

The last two have effective vaccinations. In Adelaide cats certainly need the feline enteritis vaccination but we don’t have much leukaemia virus to worry about.

Vomiting In Older Cats

There are special reasons why a mature cat might vomit that are rare in young cats. Here are the most common.

Constipation

Vomiting in an older cat can have any number of explanations but in my clinic, the number one cause is constipation. These cats usually look and act well, but are vomiting a little more often and may have lost some weight.

These are the same symptoms as the next five causes so please don’t treat your cat for constipation without seeing the vet first. Once it’s confirmed, visit our page on the treatment of constipation in cats.

The next five are all diagnosed or excluded by routine wellness blood testing.

Hyperthyroidism

Cats with excessive thyroid hormone levels commonly have a ravenous appetite. A bit like the rapid eaters and over-eaters I mentioned earlier, this can lead to vomiting after meals. Visit this page for more on thyroid problems in cats.

Chronic Kidney Disease

Kidney problems are always high on our suspicions if an older cat is vomiting but drinking more. Other signs are a reduced appetite and weight loss.

Visit here for diagnosis, staging and treatment of feline kidney failure.

Pancreatitis

There is no doubt that we are still missing some cats with pancreatitis despite having a new test. The good news is that we’re much more aware of it than we used to be, and treatment is generally successful.

Liver disease

Cats get a range of liver diseases, but especially cholangiohepatitis. It requires a biopsy to diagnose but is then usually easy to manage.

Diabetes

Diabetes in cats is another common disease, especially of the overweight and middle-aged. It’s not at all a death sentence with modern insulin choices like glargine.

IBD

What we call IBD or inflammatory bowel disease is really a very poorly understood chronic problem. It causes vomiting, diarrhoea and weight loss over many months. Intestinal biopsies are essential for its diagnosis. Read more about IBD in cats here.

Neoplasia

The most common cancer of the gut in cats is small cell lymphoma. It looks exactly the same as IBD until biopsies are done, but is quite treatable once diagnosed.

Many other tumours and cancers can affect the gut of older cats just like many other species. Most can be removed if diagnosed via ultrasound in time.

Related: Causes of vomiting in dogs.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

I’m going to use the evidence and my experience to help you decide if blood tests are a good idea for your pet. I’ll start by answering the question: when are blood tests useful? Then I’ll discuss the downsides.

How Often Are Blood Tests Abnormal?

The odds are low but definitely not zero. Three recent studies have looked at how often significant abnormalities are found in apparently healthy dogs and cats:

• 20 out of 1293 young dogs (1.5%).
• 3 in 100 middle-aged and old cats (3%)*
• 11 in 406 dogs aged 6 to 9 (2.7%)**
• 5 in 130 cats aged 6 to 9 (3.8%)**

From this, I roughly estimate that 1 in 70 young animals, and 1 in 25 in middle age, will benefit from blood testing. Tests will be even more useful for:

• The elderly
• When we can’t get a good physical exam
• When a pet’s history is unknown
• Breeds prone to certain conditions

It’s up to each owner to decide if risks like these can be accepted. Personally, I choose to test my pets from 7 years of age, but I applaud puppy owners who want testing done before desexing. This can act both as a useful check for some congenital diseases and a baseline set of values for future tests.

The most common abnormalities we find are kidney or liver disease. Just like my dog Tinker, they can be treated if found early and modified anaesthetics can still be given safely.

How Much Does Blood Work Cost?

Prices will vary between clinics but the typical fees can be found on our pricelist here.

What Are The Negatives Of Blood Work?

Now for the downside. Apart from cost, there are two important reasons why blood testing needs consideration:

Stress & Anxiety

Stress and anxiety need to be recognised with any veterinary procedure. I painfully recall a case where a very educated owner wanted her tiny puppy to have a special blood test. I should have gently explained why it wasn’t a good idea. Instead the poor thing had a terrible experience that could have been avoided. How?

Easy. If I had waited until the day of the anaesthetic I could have taken it with no extra stress. We draw the blood directly from the intravenous line we place before surgery.

Most of the time, dogs and cats tolerate blood testing well, and we encourage you to stay with your pet to offer support. Occasionally the negatives of stress outweigh the positive benefits of testing.  You can usually trust us to advise you on this.

False Positives

Every pet owner needs to know that tests are never 100% reliable. For any single test, there’s a 5% chance of it looking abnormal when it’s actually OK. Once you test 20 values, that number jumps to 64%. The reasons for this have to do with the natural variation that occurs in nature.

When I review any pet’s blood test results, there is almost always something that looks wrong. My job is to separate the wheat from the chaff. Most of the time it’s easy, but every now and again a ‘false positive’ will require extra tests to identify.

It’s not devastating to get this wrong as long as we don’t assume anything without proof. However, it’s always a time of worry for owners while we sort it out.

Is Blood Testing Necessary?

There isn’t one right answer. Each pet owner will have a different attitude to the risks of not testing, the costs and the downsides. Each pet will have a different risk profile depending on their age, breed, tolerance of handling and how much we can learn by other means. In the end, it comes down to a personal choice.

We’ll always be there to guide you and do whatever you ask. Or instead, you can always ask the magic question: “What would you do if it was your pet?”

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

*This study also found FIV in 14% and one urinary infection
**This study (in my opinion) over-diagnosed significant problems so these numbers are adjusted by me. I’m happy to discuss my reasoning.

Further Reading

For an in-depth look at everything we check please visit our page on what we test blood for in dogs & cats.

Paepe, D., Verjans, G., Duchateau, L., Piron, K., Ghys, L., & Daminet, S. (2013). Routine health screening: findings in apparently healthy middle-aged and old cats. Journal of feline medicine and surgery, 15(1), 8-19.

Alef, M., Von Praun, F., & Oechtering, G. (2008). Is routine pre‐anaesthetic haematological and biochemical screening justified in dogs?. Veterinary anaesthesia and analgesia, 35(2), 132-140.

Dell’Osa, D., & Jaensch, S. (2016). Prevalence of clinicopathological changes in healthy middle‐aged dogs and cats presenting to veterinary practices for routine procedures. Australian veterinary journal, 94(9), 317-323.

Is this just over-servicing or are there good reasons to check?

In the end it’s up to you to decide. Once you read Trixie’s story you may see it from our point of view.

Why Do We Do Blood Tests?

Two years ago when Trixie was ten years old, she came for her annual checkup. She seemed completely healthy but when we asked her owner if she also wanted us to take blood she said yes. Here’s why:

• The older you are the more can go wrong
• Dogs age seven times faster than humans; each annual checkup spans seven of our years
• Dogs can’t complain about feeling sick
• Good haemoglobin, kidney & liver values are vital for anaesthetics
• And what most pet owners say: we’d do it for ourselves

What Do Blood Tests Look At?

Trixie’s physical exam was 100% normal but we didn’t stop there. Our nurses do a great job of holding dogs or cats for blood testing, and so the sample was taken without distress to dog or owner.

Although we have our own in-house blood analytical machine for emergency and pre anaesthetic screening, we always send non urgent samples to an external laboratory.

Here are Trixie’s results. I’ve labelled each set of values so you can see what is included in a standard blood test. As you can see, there are a lot of readings taken from a tiny amount of blood.

We can get all of this from 1.5mL of blood. If you look at the second test you’ll see there’s even more. Sometimes I stop to remember how amazing this is.

As you can see, each value is reported with the normal range for that parameter. As you can also see, there are some abnormalities.

The job of the vet is to sort the wheat from the chaff. There are always spurious or irrelevant abnormalities. In this case, though, you can see that no-one would look at those liver enzymes and think they are OK.

Next problem:

What Happens With Abnormal Blood Results?

The first thing you need to know is that we will always call you to discuss blood results, whether they are normal or not. If you don’t hear from us within two days, check that we’ve got your best phone number, because you can bet we’ve tried.

Most of the time, abnormal results don’t give us a diagnosis. We find that something isn’t working properly or that an organ is in trouble. We still need to find out why.

Most abnormal results will result in us asking for further specific testing. Often we’ll ask you to collect a urine sample. In Trixie’s case, we started with a second blood test for Cushings Syndrome (which was negative), and then recommended an ultrasound examination.

The ultrasound showed a large mass in the liver, but indicated that there was still time to remove it. She had routine surgery to remove the mass inside its liver lobe.

Recently I saw her again and did her annual checkup. That’s her above looking fantastic. No surprises that her owner asked for another blood test. This one is a good example of the minor variations we can safely disregard.

Should My Dog Or Cat Have Blood Tests?

I like to think of blood testing as a fishing trip. You don’t know what you’re going to catch, and often you come back with nothing to show for the effort and cost (the price of Trixie’s test is listed here).

Read here how often pet blood tests are abnormal. It’s a gamble being played with very high stakes. If Trixie didn’t have her routine blood test we would never have found the tumour in time, and she would not be alive and happy today.

Common and important findings include kidney disease, liver disease, chronic pancreatitis and hormonal diseases like overactive or underactive thyroid, diabetes or cushing’s syndrome. All of these can be managed if we discover them in time. Many of them also affect how your pet copes with an anaesthetic.

Most of the time, blood testing will not be this dramatic, but we regularly see stories like Trixie’s. In the end, we will never tell you you should get blood testing done. It’s always your choice and we respect that. But I’ll bet there aren’t many vets who don’t do it for their own animals.

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.