Let’s say your pet’s been off her food for a few days. X-rays, labwork and physical examination have been less than completely rewarding. Still, everything points to something amiss with her liver. Ten or twenty years ago we would’ve jumped right into her abdomen to take a look-see. In today’s world? We’d order an ultrasound.

Ultrasound is a means of seeing what lies beneath the surface by sending sound waves into it and registering an image that corresponds to the way the waves bounce off the structures within it. It’s neat. And it can be incredibly helpful. But it’s not so easy to do as the ultrasound technician or doc typically makes it look.

Sure, a baby looks just like a baby when the ultrasound probe is aimed just right, but that’s a far cry from interpreting the vagaries of normal kidney morphology or that of abnormal liver tissue. And yet this tool is so cool an expert handler can render surgery unnecessary in cases for which we once considered it the only way to know what lurked beyond our field of vision.

But an ultrasound often carries a hefty price: anything from $50 to $500 according to my vet sources from California and Oregon to Chicago, New York and Miami. The differences in prices for this service vary less by region than they do based on the individual veterinarian performing it, his or her equipment and the type of ultrasound exam that’s offered (reproductive, abdominal, chest or extremity).

In general, ultrasounds for reproductive examinations are least expensive. In these, the vet is looking for something pretty obvious: Are fetuses present or not? Are their hearts beating or not? That’ll be fifty bucks, please—in the least pricey places. The specialized vet establishments and tonier practices will often price it out as an abdominal ultrasound—for $250-$500, depending on your luck.

The price differential in these cases often has more to do with the price of the equipment utilized. For pregnancy exams providing the most basic information, a minimally functional ultrasound machine is acceptable. These run anywhere from $5,000 to $10,000 for used equipment. At a high-end hospital, this equipment can cost as much as $200,000. And while  that kind of quality can be unnecessary for basic "are they there or not?" preg checks, it can make a huge difference in evaluating minor changes in organs and evaluating the chambers of the heart.

But there’s a lot more than equipment and luck involved in a thorough, expert examination of the chest or abdomen on ultrasound. Internists, radiologists, cardiologists (for the chest) and oncologists are the specialists most likely to offer more expensive services in the upper range (I’ve seen $200 to $500 per area or cavity, depending on the specific specialist). They do multiple ultrasounds every day. They know what they're looking at.

In many cases, ultrasound technicians (who may be either human-schooled and vet cross-trained or veterinarians who just love ultrasound) are the providers of ultrasound services. They may even be better at this diagnostic procedure than specialized vets (with the possible exception of vet radiologists, who are typically considered the undisputed experts in this field). After all, they spend their entire careers doing these studies.

The best of these ultrasound vets or techs work in conjunction with specialists to arrive at a diagnosis. Their services tend also to be priced at $200-$500 per area, depending on the quality of their equipment and the degree of their specialist assistance and their expertise.

Then there are the generalist practitioners who take an interest in ultrasound, possess the appropriate equipment, and offer more than the basic reproductive examination most of us can manage given any sort of functioning ultrasound machine.

Some of these practitioners are good at ultrasounds—very good. They have good equipment, sometimes great equipment. Most have taken advanced coursework in ultrasonography. The very best of these will even forward their findings to specialists (usually a radiologist) to interpret these images for them. They usually charge anywhere from $100-$400 per cavity depending on the quality of their equipment, degree of proficiency and utilization of a specialist for interpretation.

Then there are the hacks—vets who have access to a machine and presume to know what they’re looking at but really have little expertise. They’re also often willing to charge you over $200 just to turn on the ultrasound machine—in spite of their inexperience. All the others are worth their fees; these are the ones you need to look out for. So ask the basic questions:

1-Do you have specialized training in ultrasound techniques?

2-What kind of ultrasound machine do you have (a laptop with a USB probe is usually worth a lot less than a modern, free-standing machine)?

3-Do you have a board-certified specialist interpreting these results?

This tends to help you decide whether your money’s best spent here or at the specialty hospital, where you know your ultrasound will be evaluated by someone with a higher degree of training in this arena.

Ultrasounds can be priceless if they help you avoid surgery and arrive at a diagnosis. They’re also immensely valuable when they tell you what’s NOT there, even if they can’t help you reach a definitive conclusion. But neither of these goals is reliably achievable unless you have the right provider using the right equipment. Consider this as you make your decision on your pet’s next ultrasound-invoking healthcare crisis.