Q.  Is TK specific for LSA and HSA?

A.  TK has a high specificity for cancer; normal dogs very rarely have an elevated TK.  Its presence can be found in a wide variety of tumors.  VDxI has only studied LSA and HSA, however we believe its use may be further expanded to other types of neoplasias.  These investigations continue.  A positive TK result in conjunction with the clinical picture will provide clues as to the source of the neoplasia.

 Q.  Does the absolute value of TK have meaning?

A.  In LSA, the value of TK directly corresponds to the severity of disease.  In severe cases of LSA TK values may exceed 100 U/L.  In these cases, the patient’s prognosis is often very poor and often does not respond to chemotherapy.  The best outcomes are in cases where the TK is below 30 U/L.

 Q.  What should be done when TK is slightly elevated?

A.  If additional screening tests such as physical exam, blood work and/or body cavity images are negative, we recommend rechecking TK in 4 weeks for trending determinations.

Q.  Upon treatment, does TK return to normal?

A.  Most often yes, but in some cases it will remain slightly elevated.  In LSA, this becomes that dog’s baseline value for monitoring the return of disease.  In dog’s that are non-responders, TK values may drop only slightly or heightened values may be seen immediately post treatment.

 Q.  How frequently should I test to monitor disease?

A.  That is often a judgment call based upon the severity of disease but our recommendation is every 4-6 weeks initially post treatment.

 Q.  Can TK be used to Rule-Out HSA?

A.  Due to its high specificity, TK is best used to Rule-In HSA.  A negative TK result does not Rule-Out disease.  Low levels of TK may be found in about 25% of HSA patients.

 Q.  Can TK provide information about HSA prognosis?

A.  The prognosis of HSA is very poor regardless of the TK value.  However the best outcomes are in the early detection of HSA.

 Q.  Can TK be used to screen high risk breeds for HSA?

A.  VDxI is studying this application.