What Does Clinical Biochemistry Diagnose?
The metabolic profile blood test battery can give an initial appraisal of several organs’ functions. Along with the complete blood count (CBC), it can render both an initial global view of general health as well as pinpoint specific tests that can be used to track abnormalities at intervals. Clinical biochemistry is a crucial test for appraising organ function.
- Blood urea nitrogen (BUN): Is a waste product of protein metabolism, and its excretion falls with kidney disease, raising its level in the blood. Bun is also sensitive to dehydration.
- Creatinine: Is a waste product of muscle metabolism, which accumulates when the kidneys fail to excrete it in kidney disease.
- BUN/creatinine ratio: Is the ratio used to quantify kidney function, an elevated ratio > 20:1 indicating decrease its function.
- Calcium elevations: Indicate kidney dysfunction and predict those at risk for kidney stones. Calcium can also be used to detect abnormal parathyroid function.
- Sodium, potassium, and chloride: Are electrolytes whose balance is maintained by normal kidney function. Elevations indicate kidney disease.
- Uric acid: Can show when there is a build-up of uric acid crystallization, a prime contributor to gout.
- Albumin: Is a protein made by the liver and its level documents liver function.
- Alkaline phosphatase (ALP): Alanine aminotransferase (ALT), and Aspartate aminotransferase (AST) are biomarkers that become elevated with liver disease.
- Total protein: Another product of the liver, consists mainly of the globulin and albumin manufactured there. When low can indicate liver disease or malnutrition.
- Bilirubin: rises with obstruction in the biliary tract or in primary liver failure, such as cirrhosis. It is also elevated in neonatal jaundice, which puts an infant at risk for brain damage.
Pancreas and Glucose Metabolism
- Glucose rises when insulin falls: As it does absolutely in Type 1 DM and relatively in Type 2 DM. It is also a measure for how effectively the kidney excretes excess glucose in the blood.
- Hemoglobin A1c: Is a type of hemoglobin molecule whose affinity for glucose is used to advantage to get a long-term estimate of average glycemic control or the lack thereof.
Other Biochemical Tests:
- Arterial blood gases: Give a picture as to how well the blood is being oxygenated and carbon dioxide is being removed. This is a part of the normal acid-base balance of the body, and both the biochemical processes and respiration that drive the acid concentration (pH) up or down can fail as a complication of disease; an abnormal pH can create a vicious cycle of deterioration, because biochemical reactions need a normal pH in which to function, including the healing reactions.
- Cardiac enzymes: Useful in identifying biomarkers released from damaged heart tissue, used to diagnose cardiac events such as ischemia and infarction when there is confusion as to whether there has been a cardiac event such as a heart attack.
- Immunological tests: Such as CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate) for inflammation, rheumatoid factor (RA factor), anti-nuclear antibodies (ANA), and other immunological biomarkers can be used as part of a diagnostic work-up for specific autoimmune diseases. White blood cells (WBC) in a complete blood count (CBC) can also be used to identify immune suppression, as occurs with HIV/AIDS or chemotherapy for cancer.
- Clotting studies: Can identify D-dimers, part of the diagnostic approach to coagulation problems. The INR (international normalized ratio) is also a reflection of clotting used to titrate anticoagulation therapy in thromboembolic disease. There is a narrow range between just enough anticoagulation and too much, and the INR is used to confirm that a patient is in that range.
- Hemoglobin A1c monitors the long-term status of diabetics.
- Lipid profiles: Measure cholesterol and triglycerides, which when elevated, risk cardiovascular disease.
- Electrophoresis: Is a technique for separating out different components of one thing, for example, the types of hemoglobin a person may have, important in such diseases as sickle-cell anemia.
- Urinalysis: Of the urine can measure pH, glucose, protein, bilirubin, ketone, and nitrite concentration for kidney function and as a quick quantitation of the severity of diabetes.
- Spinal fluid examination: Can identify bacteria in it while investigating meningitis, and measure protein and glucose, which are altered with bacterial and viral infections.