Chapter 28: Clinical Chemistry
Terms in this set (105)
the science of using the chemical analysis of bodily fluids to obtain information about the clinical condition of the body.
How are chemical represented?
By an abbreviation that is the first 1 or 2 letters of the clinical name.
electrically charged chemicals.
What ions are in the human body?
Any substance in the body that contains ions (+ charged), or chemicals that have an electrical charge.
The body requires electricity to maintain what bodily functions?
-proper function of the cardiovascular and nervous systems.
What organs play a major role in electrolyte balance?
What conditions can destabilize electrolytes?
-presence of heart, kidney, or liver disorders
a condition when sodium is too low in blood
Symptoms of hyponatremia
a condition when sodium is too high in the blood
What happens when the body senses hypernatremia?
healthy kidneys retain water to dilute the sodium in the body. Results in:
-edema of tissues
-extra work for the heart
Normal blood serum level for sodium
135 to 145 mEq/L
Normal 24-hour urine measurement for sodium
40-220 mEq/day, varies with diet
A major electrolyte found in the water outside the cell.
The major positive electrolyte inside the cells and supports the contraction of skeletal and cardiac muscles.
-controlling electrical activity of the heart muscle
-breaking down carbohydrates for energy
-maintaining acid-base balance
What is the normal range for blood potassium?
3.5 mEq/L to 5.2 mEq/L
a condition when potassium is too low in the blood
What causes hypokalemia?
-people who take diuretics
-overuse of laxatives
-severe or prolonged vomiting or diarrhea
Symptoms of hypokalemia?
-abnormal heart rhythms
A condition when potassium is too high in the blood
What causes hyperkalemia?
-high blood pressure
-poor kidney function
-some heart medications
-patients with too much acid in their blood
Symptoms of hyperkalemia?
-abnormal or dangerous heart rhythms (ventricular tachycardia)
What factor results in a high potassium level?
Poor venipuncture technique
A major electrolyte outside the cell that has a negative charge.
-maintains the acid-base, or alkaline, balance in the body.
What is the normal range for chloride blood levels?
96 to 106 mEq/L
A condition when chloride is too low in the blood
What cause hypochloremia?
-congestive heart failure
A condition when chloride is too high in the blood
What conditions cause hyperchloremia?
-medications like carbonic anhydrase inhibitors used to treat glaucoma
An electrolyte with a negative charge that is formed with carbon dioxide (CO2) dissolved in the blood.
-This is the most important electrolyte used to maintain acid-base balance in the body including the pH (percentage of hydrogen) in the blood.
Normal blood carbon dioxide levels?
23 to 29 mEq/L
Neutral blood pH range in the neutral range?
7.35 to 7.45
An electrolyte found primarily inside the cell and carries a positive charge.
-Proper function of nerves and muscles.
True or False. Some laxatives and antacids contain magnesium because it is used by the body naturally to neutralize stomach acids.
Normal serum level range of magnesium
1.7 to 2.2 mg/dL
Condition in which the serum level of magnesium is below 1.5 mEq/L
What causes hypomagnesemia?
-toxemia in pregnancy
Condition that occurs when magnesium levels increase to more than 2.5 mEq/L.
What causes hypermagnesemia?
-poor excretion due to renal failure
Symptoms of hypermagnesemia
-low blood pressure
Found in the bones, this electrolyte has a positive charge.
-Plays a part in bone and teeth health
-nervous system function
Normal calcium serum level
8.5 to 10.2 mg/dL
Condition in which calcium level is too low.
Symptoms of hypocalcemia
-tingling of fingers or around the mouth
Causes of hypocalcemia
-low magnesium levels
-vitamin D deficiencies
Condition in which the calcium level in the blood is higher than normal.
Cause of hypercalcemia
-too much calcium or vitamin D in the diet
Symptoms of hypercalcemia
-nausea and vomiting
A major negative electrolyte inside the cell. Needed for:
-building genetic material
Normal serum phosphorus
2.4 to 4.1 mg/dL
True or False: Serum phosphorus and calcium levels are not closely related.
False. When one is elevated, the other one is decreased.
A serum phosphorus level less than 2.4 mg/dL.
Causes of hypophosphatemia
-decreased intake of vitamin D in the diet
a serum phosphorus level that exceeds 4.1 mg/dL
Causes of hyperphosphatemia
-too much Vitamin D/phosphate in the diet
-some medication (phosphate-containing laxatives)
What can hyperphosphatemia lead to?
A nitrogenous waste product of protein metabolism; major source of nitrogen in the urine.
Why is it important to measure the blood urea nitrogen (BUN)?
Determines kidney function (filtering abilities).
Normal range for blood urea nitrogen (BUN)
6 to 20 mg/dL
A nitrogenous waste product from the breakdown of creatine - a substance made by the body to supply energy to muscles.
Normal range for Creatinine
0.6 to 1.3
the buildup of urea and creatinine in the blood, which may result in damage to kidneys and decrease in their inability to function normally.
Creatinine clearance test
Measures the rate at which creatinine is cleared from the blood by the kidney.
How is a creatinine clearance test performed?
24 hour urine collection-first void wasted-stored on ice.
A nonprotein nitrogenous compound produced as a waste product from the breakdown of purine (substance found in certain foods).
What foods contain purine?
-dried beans and peas
Normal blood uric acid range
3.5 to 7.2 mg/dL
A condition in which elevated uric acid levels occur, resulting in uric acid crystals forming in the kidneys and/or joints.
A substance that is formed as proteins are broken down in the intestines.
Why is an ammonia blood level test performed?
-To check liver function
-diagnose metabolic alkalosis
Normal range for ammonia
15 to 45 mcg/dL
A condition that occurs with too much ammonia in the blood.
Causes of hyperammonemia
-severe liver disease
-congestive heart failure
-severe gastrointestinal bleeding
High blood ammonia levels are neurotoxic and often associated with...?
Symptoms of hyperammonemia
Hypoammonemia can be caused by...?
-certain types of hypertension
-some types of antibiotics
What types of medications control Gout?
-nonsteroidal anti-inflammatory drugs (NSAIDs)
The ability of the body to maintain the balance between acidity and alkalinity.
The way the body manages changes with pH levels.
pH below 7.35
pH above 7.45
lungs cannot work quickly enough to produce bicarbonate to neutralize the acidosis coming from the kidneys.
Causes of metabolic acidosis
-poisoning from ethylene glycol
-overdose of medications (salicylate such as aspirin)
-exercise (lactic acidosis)
A buildup of acid in the blood due to the inability of the body to remove CO2 through adequate breathing.
Causes of respiratory acidosis
-chronic lung disease (emphysema)
-overuse of sedative drugs
Causes of metabolic alkalosis
-too much bicarbonate in the blood
-ingestion of sodium bicarbonate to relieve indigestion
-extreme loss of chloride due to vomiting
-loss of potassium in patients taking diuretics
Causes of respiratory alkalosis
-lack of oxygen
-lung diseases or conditions that cause hyperventilation
Function of the liver
-takes nutrients from the digestive system, processes them, stores them, send them to different parts of the body
fat entering the blood
What does the liver remove?
-other toxins in the blood
What is produced in the liver?
What is included in Liver Function Tests?
-AST (aspirate aminotransferase)
-ALT (alanine aminotransferase)
-ALP (alkaline phosphatase)
-LD (lactate dehydrogenase)
A type of protein that speeds up a chemical reaction in a living thing
The two most useful measure of liver function?
ALT (alanine aminotransferase) and AST (aspartate aminotransferase)
Alkaline phosphate (ALP)
-present in bones, liver, intestines, kidneys, placenta
-ALP levels rise in bone and liver disorders (bile duct obstruction and primary binary cirrhosis)
Gamma-glutamyl transferase (GGT)
blood test to detect increased enzymes that can indicate cirrhosis, hepatitis, acute pancreatitis, acute cholecystitis, or nephrosis, and to test for Helicobacter pylori antibodies
Why should you always compare results with reference intervals (RIs)?
Because reference ranges for enzyme tests are the most sensitive to deviation among laboratories.
A yellowing of the skin and eyes
Produced by the normal breakdown of hemoglobin
Conjugated with glucuronic acid, water soluble
(Only type of bilirubin that can appear in urine)
bilirubin that hasn't been combined with certain sugars.
What color is bilirubin?
-A substance produced in the liver and cells of all animals.
-Oil based with a waxy appearance.
Function of cholesterol
-adding to the makeup of cell membranes
-adding to the makeup of myelin sheath surrounding neurons
-contributes to the digestive bile acids in the intestines
-assisting with the production of certain hormones (estrogen, testosterone, cortisone, and aldosterone)
-Any of a group of soluble proteins that combine with and transport fat or other lipids in the blood plasma.