HERTEST rises with tumor progression and falls when treatment is effective. 

CHECKMARK is elevated in patients with several cancer types. It's early days—the full value of monitoring immunotherapy drugs remains to be determined.


Martell Diagnostic is a CLIA reference laboratory providing HERTEST (quantitative sHER2/neu ELISA) and CHECKMARK (soluble PD-L1) tests to hospitals and physicians. Evidence for HERTEST prognostic and predictive value has been documented in more than 10,000 patients, providing actionable information to guide treatment. CHECKMARK is a new blood test to evaluate and monitor immunotherapy.

Blood Tests

HERTEST is one of several diagnostic tools available to manage women with HER2 breast cancer. HERTEST may be used to detect tumor recurrence or to monitor targeted HER2 drugs. CHECKMARK is of prognostic value to patients with lung, kidney, and other cancers. Today, use of immunotherapy drugs may  be triggered by PD-L1 tissue testing—blood testing adds accuracy.