Introduction to Clinical Chemistry Flashcards

1
Q

homeostasis

A

the tendency toward steady state or equilibrium of body processes

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2
Q

analyte

A

a chemical substance that is the subject of chemical analysis

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3
Q

preanalytical phase

A

the collection, handling and storing correctly until tests are performed

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4
Q

analytical phase

A

using correct procedures and appropriate quality assessment measures to analyze specimens

AKA quality control

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5
Q

postanalytical phase

A

reporting accurate and calculated test results

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6
Q

routine chemistry tests

A

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

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7
Q

Special chemistry tests

A

tests that are ordered less frequently

ie. hormones or certain drug levels

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8
Q

Chemistry profiles or panels

A
  • reflect general state of health

- evaluate particular organ systems

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9
Q

Specimens used for chemical analysis

A

blood and urine

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10
Q

Reference range

A
  • 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

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11
Q

factors affecting reference range

A
  • 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

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12
Q

reference range for Total Protein

A

60-80 g/L

albumins(60%) + globulins (40%)

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13
Q

Albumins

A

-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

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14
Q

hypoalbuminemia

A

low level of albumin

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15
Q

Globulins

A

a heterogeneous group of serum proteins with varied functions, 40% of total protein in serum

(total protein-albumin = globulin)

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16
Q

electrolytes

A

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

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17
Q

Mineral metabolism

A
  • Calcium, Ca (1.15-1.33 mmol/L)
  • phosphorus (0.96-1.44 mmol/L)
  • Iron (11.6-29.5 mmol/L)
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18
Q

hypercalcemia

A

blood calcium levels above normal

1.15-1.33 mmol/L

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19
Q

hypocalcemia

A

blood levels below normal

1.15-1.33 mmol/L

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20
Q

Kidney Function

A

-Creatinine (62-125 mmol/L)
-Blood Urea Nitrogen, BUN (2.9-6.4 mmol/L)
-Glomerular filtration rate, GFR
-Uric Acid (0.21-0.44 mmol/L)
Note*- elevated uric acid causes Gout

21
Q

Glomerular filtration rate

A

an estimation of how much blood passes through the glomeruli per unit of time (minute); an estimate of the number of functioning nephrons made by using the rate at which molecules such as creatinine and urea are filtered by the kidneys

22
Q

Gout

A

a painful condition in which blood uric acid is elevated and urates precipitate in joints

23
Q

Liver Function

A

Bilibrubin- a product formed in the liver from the breakdown of hemoglobin
(2.0-21.0 umol/L)

Enzymes

  • Alkaline phosphatase (ALP) (20-130 U/L)
  • Aminotransferases (ALT 3-30 I/L) (AST 10-37 U/L)
  • Gamma glutamyltransferase (GGT 3-40 U/L)
  • Lactate dehydrogenase (LDH 110-230 U/L)

*note- enzymes in the blood are unstable

24
Q

Alkaline phosphatase(ALP)

A

20-130 U/L - an enzyme widely distributed in the body, especially in the liver and bone

note liver and bone

25
Q

Aminotransferases

A

(ALT 3-30 U/L) (AST 10-37 U/L)

26
Q

Alanine aminotransferase (ALT)

A

an enzyme presents in high concentration in the liver and measured to assess liver function; formerly called SGPT
(3-30 U/L)

27
Q

aspartate aminotransferase (AST)

A

an enzyme presents in many tissues, including cardiac, muscle and liver and measured to assess liver function; formerly called SGOT
(10-37 U/L)

note* also used to assess heart

28
Q

difference between ALT and AST

A

ALT is measured to assess liver function, and AST is measured to assess liver function and heart

29
Q

Cardiac Markers

A
Creatine kinase (CK-MB)
troponins
B-type natriuretic peptide (BNP)
C-reactive protein (CRP)
Homocysteine
30
Q

Creatine Kinase (CK-MB)

A

an enzyme presents in large amounts in brain tissue, heart and skeletal muscle and a form of which is measured to aid in diagnosing heart attach within 24 hour

Total CK 30-170 U/L

31
Q

Troponins

A

intracellular proteins that are present in skeletal and heart muscle and are released when muscle is injured

32
Q

B-Type natriuretic peptide (BNP)

A

a peptide hormone released primarily from the ventricles of the heart and used as a marker for cardiac function

note*- released from the ventricles of the heart

33
Q

What is the similarity between skeletal muscle and heart muscle?

A

they are striated

34
Q

If a patient is walking with chest pain, what can we measure to see if there is a heart problem?

A

troponins

35
Q

homocysteine

A

an amino acid, elevated blood levels of which are associated with increased risk for vascular and cardiovascular disease

36
Q

Lipids

A

any one of a group of fats or fat-like substances

37
Q

Lipid metabolism

A
  • Total Cholesterol (3.6 -6.5 mmol/L) and fractions LDL, HDL, VLDL
  • Triglycerides (0.11-2.15 mmol/L
  • hyperlipidemia
38
Q

Triglycerides

A

the major storage form of lipids; lipid molecules formed from glycerol and fatty acids. fasting for 12-14 hr

(0.11-2.15 mmol/L)

39
Q

hyperlipidemia

A

excessive amount of fat in the blood plasma is milky appearance

40
Q

Carbohydrate metabolism

A

glucose (3.9 -6.2 mmol/L)

Glucose metabolism is largely regulated by insulin, which is produced by the pancreas.

Also influenced by glucagon, growth hormone, and cortisol

41
Q

Thyroid Function

A

-Thyroid-stimulating Hormone (TSH)
(0.35-5.0 mIU/L
-Thyroxine (T4)
Triiodothyronine (T3)

Other Tests:
Insulin
growth hormone
adrenocorticotropic hormone (ACTH)

42
Q

Thyroid stimulating Hormone (TSH)

A

a hormone that is synthesized by the anterior pituitary gland and regulates the activity of the thyroid gland (0.35-5.0 mIU/L)

43
Q

hyperthyroidism

A

excessive functional activity of the thyroid gland; excessive secretion of thyroid hormones Grave’s disease

44
Q

hypothyroidism

A

underactive function of the thyroid gland; abnormally low production of thyroid hormones

45
Q

What are the most common specimens used to analyze chemical chemistry?

A

blood (serum) and urine

46
Q

how long do we wait before centrifuge SST? Why?

A

30 MINUTES to let clotting activator mix well and to avoid the buildup of membrane layer

note*- the automated machine will not collect serum if membrane layer detected

47
Q

Why do we perform the glucose test when checking kidney performance?

A

Elevated sugar levels signal a variety of metabolic and structural changes in the nephrons preventing them from functioning properly

48
Q

Will we use whole blood sample in clinical chemistry department?

A

yes, we use whole blood in the lavender tube for the HBA1C test

49
Q

Problems in specimen collection and processing

A
  • hemolysis (elevate LD, AST, K)
  • hemoconcentration
  • over centrifugation
  • evaporation
  • microbial contamination
  • anticoagulant contamination