Introduction to Clinical Chemistry Flashcards
homeostasis
the tendency toward steady state or equilibrium of body processes
analyte
a chemical substance that is the subject of chemical analysis
preanalytical phase
the collection, handling and storing correctly until tests are performed
analytical phase
using correct procedures and appropriate quality assessment measures to analyze specimens
AKA quality control
postanalytical phase
reporting accurate and calculated test results
routine chemistry tests
AKA complete metabolic profile, is a group of tests performed simultaneously on a patient specimen to provide an assessment of the patient’s general condition.
ie. state of carbohydrate and lipid metabolism, liver and kidney tests
Special chemistry tests
tests that are ordered less frequently
ie. hormones or certain drug levels
Chemistry profiles or panels
- reflect general state of health
- evaluate particular organ systems
Specimens used for chemical analysis
blood and urine
Reference range
- determined by measuring the level of the substance in a portion of the general population and applying statistical methods to the data.
ie. when establishing reference range for total protein, a lab might test 100 random samples from the population and calculate the mean value and the standard deviation of the set of values. - the reference range is then determine by adding +-2
ie. the mean is 7g/dL therefore the reference range is 6-8 g/dL
NOTE: * reference value(s) can differ from recommended values
factors affecting reference range
- differ slightly according to the population sample’s geographical area and age of population.
- reference range for a substance measured in plasma vs. serum
- types of analyzers used, testing methods
Note*: each lab must supply its reference range when a test result is reported
reference range for Total Protein
60-80 g/L
albumins(60%) + globulins (40%)
Albumins
-the most abundant protein in normal plasma (60%); a homogeneous group of plasma proteins that are made in the liver and help maintain osmotic balance
Reference range for albumins 38-50g/L
hypoalbuminemia
low level of albumin
Globulins
a heterogeneous group of serum proteins with varied functions, 40% of total protein in serum
(total protein-albumin = globulin)
electrolytes
the cations and anions important in maintaining fluid and acid-base balance
Cation-a positively charged ion
Sodium, Na+ (135-148 mmol/L)
potassium, K+ (3.8-5.5 mmol/L
Anion- a negatively charged ion
Chloride, Cl- (98-108 mmol/L)
Bicarbonate HCO3- (2-28 mmol/L)
Note*- inform provider if sodium result is outside of reference range bc it is related to the relaxation and contraction of the muscle
Mineral metabolism
- Calcium, Ca (1.15-1.33 mmol/L)
- phosphorus (0.96-1.44 mmol/L)
- Iron (11.6-29.5 mmol/L)
hypercalcemia
blood calcium levels above normal
1.15-1.33 mmol/L
hypocalcemia
blood levels below normal
1.15-1.33 mmol/L