While the Rat Terrier is generally considered a healthy breed, there are some health issues that are common to the breed; and some issues that have made an appearance.

As a pet owner; you may not feel the need to test your dog, but if you are going to participate in high activity sports; or you are considering breeding your dog(s); you will want to consider testing your Rat Terrier for the following issues.

Primary Lens Luxation (PLL)
DNA test – absolutely essential to the dog owner/breeder/exhibitor. Untested-afflicted dogs can have their lens luxate resulting in blindness; and an unknowing vet or owner will not realize the extent of the damage that can occur.

Carriers have a low chance of genetic luxation and clear dogs have no chance of genetic luxation.

While a general practitioner auscultation of the heart is generally considered sufficient for the Rat Terrier breed to identify heart issues, there have been occurrences of MVD (Mitral Valve Disease) and VSD (ventricular septal defect (VSD) in dogs that would otherwise have passed a general practitioner auscultation. It will be necessary to use an echocardiogram to diagnose these issues.
Hip/Elbow Dysplasia – (HD/ED)
Radiographic test – not as common in the Rat Terrier, but there are some dogs in the OFA database with hip dyplasia; so if you are breeding or buying or competing; it may make sense to use dogs that are tested or from tested parents.
Patellar Luxation
General practitioner manipulation – As dogs get smaller; there is a tendency for the knee cap to form improperly; and this condition can be genetic (an anomaly can be passed on from parent to offspring)
Legg-Calves-Perthes – (LCP)
Radiographic test – Can be taken from the Hip Dysplasia radiographs

Legg-Calve-Perthes Disease (LCP) is a disorder of hip joint conformation occurring in both humans and dogs. LCP results when the blood supply to the femoral head is interrupted resulting in avascular necrosis, or the death of the bone cells.

BAER test (Hearing)
General practitioner experienced in BAER testing – Dogs with extreme white markings about the head area; may suffer from bilateral or unilateral deafness.