Clinical Biochemistry Menu

What Is Clinical Biochemistry?

Clinical Biochemistry

Blood carries a history of its interactions with both physiologic and disease processes. The balance of chemical reactions makes possible homeostasis, the stable equilibrium that defines health. Blood tests can identify abnormal processes that jeopardize homeostasis, from the specific imbalance among electrolytes to the pH (acidity) of the blood that is the end-result of illness.

Tests for Identifying Parameters of Health vs. Illness

The Metabolic Profile: When speaking of clinical biochemistry, the starting point is the metabolic profile, which tests an entire battery of physiologic functions specific to different organs by measuring the amounts of individual products from these organs.

Kidney Function

  • Blood urea nitrogen (BUN): BUN is a waste product of protein metabolism, and its excretion falls with kidney disease, raising its level in the blood. It is also sensitive to dehydration.
  • Creatinine: A waste product of muscle metabolism, which accumulates when the kidneys fail to excrete them in kidney disease.
  • BUN/creatinine ratio: An elevated ratio > 20:1 indicates decrease in kidney function.
  • Calcium: elevations indicate kidney dysfunction and predict those at risk for kidney stones.
  • Sodium, potassium, chloride: Electrolytes whose balance is maintained by normal kidney function. Elevations indicate kidney disease.

Liver Function

  • Albumin: protein made by the liver and documents liver function.
  • Alkaline phosphatase (ALP), Alanine aminotransferase (ALT), and Aspartate aminotransferase (AST): biomarkers elevated with liver disease.
  • Total protein: Mainly, globulin and albumin.
  • Bilirubin: rises with obstruction in the biliary tract or in primary liver failure, such as cirrhosis.

Pancreas

  • 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.

Other Biochemical Tests

As adjuncts to the metabolic profile, other tests can delve more specifically into directions indicated by the metabolic profile results.

  • Blood gases, drawn from an artery, give a picture as to how well the blood is being oxygenated and how well carbon dioxide is being removed. This is a part of the normal acid-base balance of the body, and both biochemical processes and respiration can drive the acid concentration (pH) up or down, which complicates further the illnesses that create the abnormal pH, because biochemical reactions need a normal pH in which to function, including the healing reactions.
  • Cardiac enzymes are useful in identifying biomarkers released from damaged heart tissue, used to diagnose cardiac events such as ischemia and infarction.
  • 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 immunologic diseases.
  • Clotting studies can identify D-dimers, part of the diagnostic approach to coagulation problems. The INR is also a reflection of clotting used to titrate anticoagulation therapy in thromboembolic disease. Hemoglobin A1c, for monitoring 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.

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.

Kidney 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 buildup of uric acid crystallization, a prime contributor to gout.

Liver Function

  • 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.

Management of Clinical Biochemistry

Clinical biochemical tests are used to examine fluids in the body (blood, urine, cerebral spinal fluid, and collections in joints, abscesses, and body cavities). Besides establishing a diagnosis, they can also be used for tracking the progress of disease management. Below are some of the more common illnesses that depend on biochemical testing in management and treatment.

Diabetes

Diabetes relies completely on blood testing for its successful management and treatment. While a fasting blood glucose is an effective screen for narrowing down the more suspicious individuals in the general population, once diagnosed, both Type 1 DM and Type 2 DM are followed by interval measurements of the glycated hemoglobin A1c, which gives a months-long appraisal of glycemic control. A normal levels in non-diabetics is <6%, but in established diabetics, a target goal of 7% is ideal in preventing DM complications.

Diabetics are at increased risk for cardiovascular disease, lipid abnormalities, and kidney failure, so cardiac enzymes (if there has been chest pain or an abnormal ECG), cholesterol and triglyceride measurements that indicate the need for statin medication, and appraisals of kidney function are important parts of diabetic management.

Immunosuppression

Doctor-caused immunosuppression, e.g., chemotherapy, can be quantitated to adjust dosages and the timing of intravenous anti-cancer therapy.

RF (rheumatoid factor) and ANA (antinuclear antibody), when positive, can make the difference in whether a person is treated for age-related osteoarthritis or immunological rheumatoid arthritis.

Thyroid Disease

When the thyroid function is low (hypothyroidism) or high (hyperthyroidism), metabolism is severely affected. The brain’s pituitary gland acts accordingly by either lowering thyroid stimulating hormone (TSH) or making more. The TSH serves as a screen for thyroid dysfunction and its normal value can indicate successful management with medication used to stabilize thyroid function.

Liver Disease

The enzymes and proteins of the liver can be quantitated to guide the on-going therapy for liver disease and to predict the levels of liver failure that may have to be taken into account in long-term management. Bilirubin is an exact reflection of liver disease, and the severity of clinical jaundice is proportionate to elevated bilirubin in the blood and urine.

Kidney Disease

Electrolyte balance based on hydration can be followed exactly with blood tests, upon which is based medication choices for diuresis or kidney function.

Dyslipidemia and Its Complications, Atherosclerosis and Cardiovascular Disease

Lipid testing is used to follow the therapeutic progress of statin drug therapy for dyslipidemia (abnormal cholesterol and triglyceride).

What Can I Prevent By Using Clinical Biochemistry?

Prevention of disease using clinical biochemistry is both by screens, to identify those at risk, and by interval assessments to prevent further disease progression.

The following, among other blood and non-blood tests, are screens used for identifying those at risk:

  • Fasting glucose: For diabetes and the hemoglobin A1c to judge how severe it has been over the previous months when the screen is positive.
  • Genetic screen for mutations: Such as the BRCA I and II, predict those at risk for ovarian, uterine, breast, and gastrointestinal cancers; CA-125 for ovarian cancer, carcinoma embryonic antigen (CEA) for other types of gynecological malignancies, and PSA for prostatic cancer.
  • Blood tests for amyloid beta: Using spectrometry, to screen for those at risk for Alzheimer disease, even decades before any onset is suspected.
  • In pregnancy: Amniotic fluid can be evaluated to determine lung maturity for a pre-term infant who may benefit from early delivery necessary due to maternal illness. Noninvasive prenatal testing (NIPT) can screen for Down syndrome and can even reveal the gender of a baby during pregnancy.
  • Testing for allergens: Via ELISA and RAST testing is used to detect allergies, but can also screen those at risk for life-threatening anaphylactoid reactions.
  • Biochemical identification of HPV in Pap smears: Can prevent pre-cancerous conditions (dysplasia) from progressing into cervical cancer.
  • Antibody screens: Are useful both to prevent blood transfusion reactions and to indicate which patients may need immunizations to prevent specific contagious diseases. They are also used to confirm successful immunization or the need for boosters.
  • Titers of blood concentrations: Can be used to screen for infectious diseases such as syphilis, but can also prevent further progress by alerting the physician when titers plateau or rise, indicating when treatment failure with one treatment modality calls for another.
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This information is provided by Vascular Health Clinics and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition.

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