24 Sep BOAS Grading Test vs Endoscopy: Which One Actually Tells You What Your Dog Needs?
If you own a French bulldog, pug, bulldog or another brachycephalic breed, you have probably heard that BOAS is hard to evaluate and that diagnosing it properly is complicated, expensive or risky. In our experience treating brachycephalic dogs at Southern Cross Vet, that reputation is largely undeserved. BOAS can be assessed clearly, consistently and safely, provided the right diagnostic approach is used.
This article compares the two main methods used to assess brachycephalic obstructive airway syndrome, the respiratory function grading scheme and endoscopy, and explains why one gives owners and vets a far more useful answer than the other. It draws on the experience of Dr Sam Kovac, who has personally performed over 1500 BOAS surgeries and assessed thousands of brachycephalic dogs for airway function.
Brachycephalic Dogs Symptoms: What Is BOAS?
Brachycephalic obstructive airway syndrome, or BOAS, is a condition affecting flat-faced dog breeds whose airway anatomy makes it harder to breathe normally. French bulldogs, pugs, bulldogs, boxers and similar breeds are commonly affected. The condition develops because of a combination of narrowed nostrils, an elongated soft palate, a narrowed windpipe and, in more advanced cases, changes to the larynx.
Common symptoms in brachycephalic dogs include loud snoring or snorting, noisy breathing during exercise, exercise intolerance, overheating in warm weather, regurgitation after eating, and collapsing or fainting during exertion or excitement. Not every affected dog shows every symptom, and severity varies significantly between individual dogs, even within the same breed and litter. This is exactly why a proper BOAS test matters. Guessing based on symptoms alone is not reliable, and not every brachycephalic dog with mild symptoms needs surgery.
What Is a BOAS Test?
A BOAS test is any structured assessment used to determine whether a dog has brachycephalic obstructive airway syndrome and how severe it is. The two main options are the respiratory function grading scheme, a physical exercise based test, and endoscopy, a direct visual examination of the airway under light sedation. Both are described as a BOAS test, but they measure very different things and are used for different purposes.
What Is BOAS Grading? The Respiratory Function Grading Scheme Explained
BOAS grading usually refers to the respiratory function grading scheme, an exercise based assessment adopted by breed clubs to screen dogs for breeding soundness. During this grading scheme, a dog is assessed at rest and then walked or trotted for a set period, with breathing sounds, effort and recovery time scored to assign a functional grade. This structured approach was developed specifically because unassisted judgement of a brachycephalic dog’s breathing had proven unreliable, since owners and even vets can normalise noisy breathing as simply part of the breed. Grading against a consistent scale, and validating that scale against objective breathing measurements, is exactly how researchers addressed that problem.
The respiratory function grading scheme is a valuable screening tool at a population level. It gives breed clubs a consistent way to flag dogs whose airway function may affect their suitability for breeding. However, it has real limitations for individual clinical decision making. It does not show a vet what is physically happening inside the airway; it can be influenced by ambient temperature, fitness and anxiety on the day, and it says little about which specific structures, such as the soft palate, nares or larynx, are contributing to the problem.
What Is an Endoscopy BOAS Assessment?
An endoscopy BOAS assessment is a direct examination of a dog’s airway using a small camera, performed under a light, short-acting anaesthetic. This allows the vet to see the soft palate, nasal passages, throat and larynx clearly, and to grade each structure individually rather than relying on an overall exercise score. At Southern Cross Vet, this is carried out using the same human-grade anaesthetic monitoring equipment we use for every procedure, so your dog’s vital signs are tracked second by second throughout.
During an endoscopy for BOAS, the vet can identify an elongated or thickened soft palate, stenotic nares, everted laryngeal saccules and, in more advanced cases, early laryngeal collapse. This gives a precise, structure by structure picture of what is actually affecting the dog’s breathing, rather than an indirect estimate based on exercise tolerance.
Grades of Laryngeal Collapse Your BOAS Test Should Identify
Laryngeal collapse in brachycephalic dogs is conventionally described in three stages.
Stage I involves eversion of the laryngeal saccules, the earliest and most reversible stage.
Stage II involves loss of rigidity and medial displacement of the cuneiform cartilages, indicating a more advanced and longer standing airway obstruction.
Stage III is the most severe, with collapse of the corniculate cartilages and loss of the dorsal arch of the airway opening.
This staged grading system is only possible with a direct visual assessment. Research has also shown that successful BOAS surgery measurably reduces a dog’s functional grading score, giving vets a concrete, numeric way to track improvement rather than a vague impression. It is one of the clearest examples of how quantifiable BOAS diagnosis actually is when the right diagnostic tool is used.
BOAS Grading Test vs Endoscopy: Which BOAS Test Gives the Better Answer?
The respiratory function grading scheme and endoscopy are often presented as competing options, but they answer different questions. The grading scheme asks how a dog performs functionally during exercise. Endoscopy asks what is structurally happening inside the airway.
For breeding assessments and population level screening, the respiratory function grading scheme has a clear role. But for an individual dog showing brachycephalic dogs symptoms, and particularly for any owner considering surgery, endoscopy gives a far more useful and quantifiable answer. It allows a vet to grade each affected structure precisely, explain exactly what is contributing to a dog’s symptoms, and determine whether that dog is a genuine candidate for surgical correction.
At Southern Cross Vet, our recommendation for dogs showing signs of BOAS is a veterinary airway assessment built around endoscopy. It removes the guesswork, replaces vague exercise based impressions with a clear structural diagnosis, and directly informs whether surgery is appropriate, and if so, exactly which structures need to be addressed.
Why the BOAS Test for Dogs Matters: BOAS Isn’t Right for Every Brachycephalic Dog
Not every brachycephalic dog needs BOAS surgery, and not every dog with mild symptoms will benefit from it. This is precisely why a proper BOAS test for dogs, ideally endoscopy, matters so much. Operating without a clear diagnostic picture risks either missing a dog that genuinely needs surgery or recommending surgery for a dog whose symptoms are mild and manageable. A thorough endoscopic assessment allows Dr Sam Kovac and the Southern Cross Vet team to make that call with confidence, based on what is actually happening in each individual dog’s airway rather than assumptions based on breed alone.
Is BOAS Surgery Risky?
BOAS surgery has a reputation for being risky, largely because brachycephalic breeds carry higher general anaesthetic risk than other dogs. At Southern Cross Vet, we manage this with human grade anaesthetic monitoring equipment, dedicated veterinary anaesthetist support for higher risk patients, a minimally invasive surgical approach, and a highly experienced team led by Dr Sam Kovac, who has personally performed over 1500 BOAS surgeries. Most patients go home the same day. With the right diagnostic assessment beforehand and an experienced surgical team, BOAS correction is a well established, predictable procedure rather than the high risk gamble it is sometimes made out to be.
Frequently Asked Questions About BOAS Testing and Grading
How do I know if my dog needs BOAS surgery?
Watch for noisy breathing, snoring, exercise intolerance, overheating and regurgitation, particularly in French bulldogs, pugs, bulldogs and other flat faced breeds. If you notice these brachycephalic dogs symptoms, the next step is a proper BOAS test, ideally an endoscopic airway assessment, rather than guessing based on symptoms alone. Book a BOAS airway assessment with our team to get a clear answer.
How much is a BOAS test?
The cost of a BOAS test depends on whether you are having a respiratory function grading scheme assessment for breeding purposes or an endoscopic airway assessment for clinical diagnosis. Southern Cross Vet offers a free BOAS airway assessment appointment so owners can understand their dog’s airway health before committing to any further testing or surgery.
How do you calculate respiratory rate on a dog?
To calculate respiratory rate, count the number of breaths your dog takes in 30 seconds while they are calm and at rest, then multiply that number by two to get breaths per minute. A normal resting respiratory rate for most dogs falls within a well established range, though this can vary with breed, age and temperature. A consistently elevated resting respiratory rate, particularly alongside snoring or noisy breathing, is a reason to book a veterinary assessment.
What are the different grades of laryngeal collapse in dogs?
Laryngeal collapse in dogs is staged in three parts. Stage I is eversion of the laryngeal saccules and is the earliest, most reversible stage. Stage II is loss of rigidity and medial displacement of the cuneiform cartilages. Stage III is collapse of the corniculate cartilages and represents the most severe, advanced obstruction. These stages can only be accurately determined through direct endoscopic examination, which is why an endoscopy BOAS assessment is the more informative BOAS test for an individual dog’s surgical planning.
What are the signs of BOAS?
The signs of BOAS include loud snoring and snorting, noisy or laboured breathing during exercise, reduced exercise tolerance, overheating in warm weather, regurgitation, and collapsing or fainting during exertion or excitement. Severity varies between individual dogs, which is why symptoms alone should not be used to decide whether surgery is needed, and why a formal BOAS test for dogs matters.
What is a BOAS test?
A BOAS test is a structured assessment used to diagnose and grade brachycephalic obstructive airway syndrome in dogs. The two main forms are the respiratory function grading scheme, an exercise based functional test, and endoscopy, a direct visual examination of the airway structures under light sedation.
What is an endoscopy for BOAS?
An endoscopy BOAS assessment is a procedure where a vet uses a small camera to directly examine a dog’s soft palate, nasal passages, throat and larynx under a light, short acting anaesthetic. It allows each airway structure to be individually assessed and graded, giving a precise diagnostic picture that guides surgical planning.
What is BOAS grading?
BOAS grading most commonly refers to the respiratory function grading scheme, an exercise based assessment used by breed clubs to screen dogs for breeding soundness. It scores a dog’s breathing effort and recovery after a set period of exercise, giving a functional grade rather than a structural diagnosis.
What is the BOAS test for dogs?
The BOAS test for dogs typically involves either an exercise based respiratory function grading scheme assessment or an endoscopic airway examination performed at a veterinary hospital. During an endoscopic BOAS test, your dog is given a light, short acting anaesthetic so the vet can directly view and grade the soft palate, nares, throat and larynx, providing a clear structural diagnosis to guide any treatment decisions.
Get a Clear BOAS Test Result, Not a Guess
BOAS does not need to be hard to evaluate, and it does not need to be treated as a high risk unknown. With the right diagnostic approach, primarily a thorough endoscopic airway assessment, brachycephalic obstructive airway syndrome can be identified, graded and treated with confidence. Dr Sam Kovac and the Southern Cross Vet team have assessed and treated thousands of brachycephalic dogs, with Dr Kovac personally performing over 1500 BOAS surgeries using a minimally invasive approach that allows most patients to go home the same day.
If your dog is showing signs of BOAS, find out exactly what is happening in their airway. Learn more about our fixed price BOAS surgery service in Sydney. or
Reviewed by Dr Sam Kovac BVSc (Merit), senior veterinarian at Southern Cross Vet, who has performed over 1500 BOAS surgeries.
Dr Sam followed his dream of becoming a veterinary surgeon which began at age three. Since then, he has developed a strong interest in oncology, internal medicine and animal behaviour. Dr Sam continues his passion for providing the most up-to-date care to his patients and their two-legged family.