The biological terrain assessment or BTA is a set of tests used to measure the pH, resistivity, and redox of a person's urine, blood, and saliva. The usefulness of the test is debatable. It is often associated with homeopathy and holistic health.
Usefulness
Proponents of the BTA claim that comparing the pH, resistivity, and redox of the blood, urine, and saliva provides a health practitioner an indication of the metabolic processes taking place inside the body. There is no scientific evidence that these measurements provide a medically relevant indication of metabolic processes. Multiple manufacturers of BTA equipment have been prevented from selling their equipment in the United States because they lack Food and Drug Administration (FDA) approval. However, the FDA has not stated whether the BTA is medically useful or not.
When it comes to medical instrumentation there really isn't such a thing as "approval." The Quantitative Fluid Analyzer (QFA) manufactured by Health Science Company does have FDA classification as a "laboratory instrument for medical purposes" "ion selective". Class 1 510(K) exempt. The Classification must be renewed every year. However it does not have CLIA (Clinical Laboratory improvement Amendment, 1988) waiver even though its in-vitro test has no misdiagnosis risk of morbidity or mortality as outlined in the Congressional Record when the CLIA law was passed. The FDA can make/modify their own laws.
The test provides a window into background body chemistry for digestion and toxicity for the purposes of lifestyle and dietary improvement progress. No diagnosis for a disease or condition is made by the instrument. Insurance will not pay for this test.