Clinical Chemistry:
Clinical chemistry is a/an:
- Quantitative science
- Serves to measure analytes in the human body (biologically important substances)
- Tests are compared to references or standards to provide accuracy of measurement of analyte concentration
- Aids in diagnosis of disease
Analytes:
Ions, Salts, Minerals:
Ions, salts and minerals include the body's important electrolytes, needed for proper muscle, nerve, and cardiac function. Dehydration, volume overload, and many medical conditions can upset the balance of the electrolytes. Electrolytes are elements that have become charged particles (ions). Positively-charged ions are called cations. Negatively-charged ions are called anions. They include the following:
- Potassium (K+)
- Sodium (Na+)
- Calcium (Ca2++)
- Magnesium (Mg+)
- Phosphorous (Ph)
- Chloride (Cl-)
- Carbon dioxide (CO2)
- Iron (Fe)
- Lead
Metabolites:
Metabolites are. They include the following:
- Glucose
- Lactic acid (LA)
- Urea
- Ammonia (AMM)
- Bilirubin (Bili)
- Cholesterol
- Creatinine
- Triglycerides
- Cystatin C
Therapeutic Drugs:
Therapeutic drugs are. They include:
- Vancomycin (VANC)
- Valproic acid (VPA)
- Digoxin
- Phenytoin
- Theophylline
Drugs of Abuse (DOA):
Drugs of abuse are. They include:
- Cocaine
- Opiates
- Cannibinoids
- Barbituates
- Amphetamines
Toxicology:
- Alcohol (ETOH)
- Salicylate (Aspirin)
- Acetaminophen (Tylenol)
Large Macromolecules:
Proteins:
- Albumin
- The most common serum/plasma protein (accounts for at least 50%)
- Produced in the liver
- Transporter Protein (of thyroid hormones, fatty acids, fat-soluble hormones, unconjugated bilirubin, drugs, etc...)
- Regulate blood volume and oncotic pressure
- Low: hypoalbuminemia
- Liver disease
- Nephrotic syndrome (kidneys)
- Burns
- Malabsorption (gluten-intolerance, Crohn's, etc...)
- Malnutrition
- Malignancy
- Pregnancy (normal)
- Liver disease
- High: hyperalbuminemia
- Diabetes
- Dehydration
- Vitamin A deficiency
- Diabetes
- The most common serum/plasma protein (accounts for at least 50%)
- Transferrin
- Haptoglobin
- Ferritin
- Total Protein (TP)
Enzymes:
Enzymes often end in "ase."
- Lipase
- Catalyzes (kicks off/speeds up) hydrolysis of fats
- Plays a key role in digestion
- Transports and processes dietary lipids
- Aids in the diagnosis of acute pancreatitis and pancreatic disorders
- Amylase
- Catalyzes the breakdown of starch (hydrolysis into sugars)
- In our saliva, where the process of chemical digestion begins
- Alanine aminotransferase (ALT)
- Most commonly found in the liver
- Also present in blood and other tissues
- Biomarker for liver health and inflammation
- Detects hepatocellular injury
- Significant elevation:
- Viral hepatitis
- Diabetes
- Congestive heart failure
- Liver damage
- Bile duct issues, such as gallstones
- Infectious mononucleosis
- Myopathy
- Some types of drugs will elevate it
- Viral hepatitis
- Most commonly found in the liver
- Aspartate aminotransferase (AST)
- Is a key enzyme in amino acid metabolism
- Found in the liver, cardiac and skeletal muscles, kidney, brain, and red blood cells
- Is a key enzyme in amino acid metabolism
- Alkaline phosphatase (AlkP)
- Plays a key role in metabolism within the liver
- Biomarker for hepatitis
- Elevated in:
- Biliary obstruction
- Hepatitis
- Cirrhosis
- Many other diseases
- Biliary obstruction
- Plays a key role in metabolism within the liver
- Lactate dehydrogenase (LD or LDH)
- Biomarker for liver cancer, liver disease, anemia, acute pancreatitis, and other diseases
- Biomarker for liver cancer, liver disease, anemia, acute pancreatitis, and other diseases
- Creatine kinase (CK)
- An enzyme found in tissues
- Its elevation indicates damage
- An enzyme found in tissues
Specific Immune Proteins: Immunoglobulins (Antibodies), Antigens and Complement (Opsinins)
Proteins of the immune system are known as immunoglobulins, or antibodies.
- IgG
- Provides the majority of antibody-based immunity
- Only antibody that can cross the placenta and give passive immunity to the fetus
- IgA
- This is the antibody that is present in the mucous membranes and in secretions
- IgE
- This antibody is involved in inflammation and allergic response
- It is associated with mast cells of the immune system as it activates them and activates basophils
- Binds to allergens and triggers them to release histamine
- This antibody also attacks parasitic worms
- IgD
- Not much is known about this antibody and much is yet to be discovered, however, what is known is that this antibody is secured to the surface of the B-lymphocyte
- Activates mast cells
- Activates basophils
- IgM
- This is the largest antibody and it forms large antibody complexes
- Found on the surface of B cells and is also secreted
- Antibody complexes involving IgM are linked to autoimmune diseases such as SLS, RA, glomerulonephritis of the kidneys, rheumatic fever, heart and joint damage, and others
- Involved in humoral immunity and destroys pathogens prior to the release of IgG
- The Complement System of the Human Immune System
- This is a system of special proteins that "help" the innate immune system phagocytes and antibodies to attack and get rid of microbes, cellular debris, and cancer cells
- They coat the surface of the target cell
- Enzymatic action kicks off a highly regulated cascade of proteins that utilize potent enzymes to "poke holes" in the cell membrane of the target cell to damage it and cause it to die
- There are several pathways: classical, alternative and lectin
- This system promotes inflammation, and it plays a role in autoimmune diseases
- They are made by the liver
- Complement C3
- Complement C3 is part of the body's complement system, which is a crucial component of the body's immune defense system responsible for killing bacteria and viruses that cause disease
- It is part of innate immunity
- C3 is the most important complement protein and the most abundant one
- C3 is measured to aid in the diagnosis of autoimmune diseases, most importantly, Systemic Lupus Erythematosis (SLE), along with C4, because they are both typically low in this disease, whereas in other types of autoimmune diseases, often just one of the complement proteins is low
- Normal reference range: 80-160 mg/dL
- It needs to be activated for both complement system pathways of the immune system
- Opsonizer
- Complement C4
- C-reactive protein (CRP)
Lipoproteins:
Lipoproteins are cholesterol markers. They include:
- High density lipoprotein (HDL)
- Low density lipoprotein (LDL)
- Lipoprotein (a)
Diabetes Marker:
- Hemoglobin A1C (HbA1C) (GHGB, or glycosylated hemoglogin)
- This common test is used to aid in the diagnosis of type 1 and type 2 Diabetes mellitus, and is also utilized to monitor treatment and progress of the disease and if its being managed well
- It is the primary test used in the diagnosis of type 1 and type 2 Diabetes mellitus
- Reflects the average blood glucose level for the past 2-3 months
- Detects what percentage of hemoglobin is covered with glycosylated sugar
- The higher the level, the more poorly the diabetes is being managed
- A high level puts a person at higher risk for complications from diabetes, including diabetic ketoacidosis
- This test is recommended once a year for those with prediabetes as a screening test
- This test is recommended twice a year for those with type 2 Diabetes mellitus who are not insulin-dependent and who are managing their blood sugar with diet and exercise
- This test is recommended 3-4x a year for those with type 1 Diabetes mellitus
- This test is recommended 4x a year for those with type 2 Diabetes mellitus who are insulin-dependent
- This is a non-fasting test
- The test may be falsely low if someone has a chronic bleeding condition or a bleed such as a GI bleed, hemolytic anemia, or have had a recent blood transfusion or have an uncommon hemoglobin variant type
- This test may be falsely high if a person has iron-deficiency anemia
- GHCB (another name for the same test)
Common Test Panels:
Electrolyte Panel:
- Na+, K+, Cl-, CO2
Liver Panel:
- Albumin
- Total protein (TP)
- Alkaline phosphatase (AlkP)
- AST
- ALT
- Bilirubin direct
- Bilirubin total
Basic Metabolic Panel (BMP):
- Na+, K+, Cl- CO2, glucose, BUN, creatinine
Comprehensive Metabolic Panel (CMP):
- Na+, K+, Cl- CO2, Ca+, glucose, BUN, creatinine, urea, TP, albumin, ALT, AST, AlkP, Bili (total)
Lipid Panel/Profile:
- Total cholesterol, LDL, HDL, Triglycerides
- This panel of tests is used to aid in the diagnosis of cardiovascular conditions, pancreatitis, some genetic diseases, and other diseases such as alcoholic and non-alcoholic fatty liver disease
Cardiac Enzymes:
- Troponin, CKMB, CK, CPK
- Troponin
- This is a protein released with the heart is damaged because this protein is found in cardiac and in skeletal muscles
- The highest (most elevated) amounts are released within 2 hours of a myocardial infarction
- Three subunits:
- Troponin C
- Troponin T
- A positive Tpn T result, along with an abnormal EKG wavelength pattern, coronary artery intervention and ischemia are indicative of an acute myocardial infarction (MI)
- A positive Tpn T result, along with an abnormal EKG wavelength pattern, coronary artery intervention and ischemia are indicative of an acute myocardial infarction (MI)
- Troponin I
- The higher the level of troponin, the more likelihood there is heart damage, especially within 3-4 hours after a heart attack and up to 14 days afterwards
- This test is commonly done along with CK, CPK, CKMB, EKG and Echocardiogram in the diagnosis of acute myocardial infarction
- False elevations can occur due to:
- Vigorous exercise
- A burn
- Sepsis infection
- Myocarditis (inflammation of the heart muscle)
- Endocarditis (inflammation of the heart valves)
- Pericarditis (inflammation of the heart sac)
- Certain medications
- Cardiomyopathy (weak heart)
- Heart failure
- Kidney failure
- Pulmonary embolism
- Hypothyroidism
- Diabetes
- Stroke
- GI bleed
- CKMB: Creatine-Kinase Muscle Brain
- This is an enzyme and a cardiac marker used to diagnose an acute myocardial infarction (heart attack)
- CK: Creatine-Kinase
- This is an enzyme and a cardiac marker used to diagnose an acute myocardial infarction (heart attack), rhabdomyolysis, muscular dystrophy, acute kidney injury
- CK 1 (CK-BB)
- CK 2 (CK-MB)
- CK 3 (CK-MM)
- CK 1 (CK-BB)
- This is an enzyme and a cardiac marker used to diagnose an acute myocardial infarction (heart attack), rhabdomyolysis, muscular dystrophy, acute kidney injury
- CPK: Creatine-Phosphokinase
- This is an enzyme and a cardiac marker used to diagnose an acute myocardial infarction (heart attack)
- Troponin
- NOTE: Exercise can cause the CK to become and remain elevated for up to a week, and troponin is a more accurate and sensitive test for acute myocardial infarction
- BNP: Brain Natriuretic Peptide
- Useful in diagnosis of congestive heart failure
- Useful in diagnosis of congestive heart failure
- NT-proBNP
- More precise than BNP
- New assay that is 8-10x more concentrated than BNP
- It's half life is two hours
- Useful in the diagnosis of congestive heart failure
- More precise than BNP