BIOMEDICAL ANALYTICAL CHEMISTRY
This particular aspect of analytical chemistry is the outcome of the unique amalgamation of the principles and techniques of analytical chemistry and biochemistry and was initially termed as ‘clinical chemistry’ but is more recently and more descriptively known as ‘biomedical analytical chemistry’.
Presently, both serum and urine assays are being used extensively in diagnostic medicine which evidently signifies that the pharmacist of today should be fully conversant with the ever-increasingly important techniques of biomedical analytical chemistry. It is, however, necessary to make a passing reference to microbiological assays and haematological assays, also being carried out in a clinical laboratory, though it should not be treated under this topic since these methods are outside the scope of biomedical analytical chemistry.
Classical example of SGOT-PAS episodes : Patients suffering from tuberculosis (TB) when diagnosed with para-aminosalicylic acid (PAS) invariably showed elevated serum levels of the intracellular enzyme serum-glutamic-oxaloacetic-transaminase (SGOT) which was initially considered and treated as a drug-induced hepatic toxicity. Later, an extensive and intensive studies revealed this to be an absolutely false diagnosis. In fact, the apparent enhanced SGOT levels were actually caused on account of the interference of PAS in the SGOT assay.
In the same vein, such analytical and biochemical interferences with respect to drug interference in various biomedical assays are being profusely cited in current scientific and research journals, such as the American Journal of Hospital Pharmacy and Clinical Chemistry.
It has been established beyond any doubt that analytical interferences can only take place when a drug or its resulting metabolite happens to interfere with the analytical method adopted for the assay.
In order to have a comprehensive account on the various aspects of ‘Biomedical Analytical. Chemistry’, we may have to study the following four methods of assay with specific emphasis on their principle and applications, namely :
(a) Colorimetric Assays,
(b) Enzymatic Assays,
(c) Radioimmunoassays, and
(d) Automated Methods of Clinical Analysis.