Hyper- and Hypoglycemia

Question 1

fasting vs. random vs. critical glucose

Answer 1

fasting: >8h since any food or drink was consumed
random glucose: anytime
critical: symptoms may appear; demand immediate medical attention and must be phoned to the physician

Question 2

glucose tolerance

Answer 2

fixed dose at fixed collection times

Question 3

what happens to glucose if left unspun?

Answer 3

• glucose decrease following collection
• left unspun = 0 after 24 h
• increase in K, inorganic phosphate, lactate dehydrogenase

Question 4

solutions to glucose left unspun

Answer 4

• use preservatives (sodium fluoride, iodoacetate)
  OR
• centrifuge blood sample to remove serum or plasma from RBC as soon as possible

Question 5

T or F. glucose is normally present in urine

Answer 5

F! absent
- overflow: when plasma glucose > 11 mmol/L; uncontrolled DM or kidney damage
- defects in tubular reabsorptive mechanisms
> glucosuria when plasma glucose >8 mmol/L
> pre-existing condition aggravated during pregnancy

Question 6

Low CSF glucose

Answer 6

bacterial meningitis
fungal meningitis = quantitate ethanol
meningeal carcinomatosis
sarcoidosis of CNS

Question 7

T or F. CSF glucose levels unaffected in viral meningitis

Answer 7

T!

Question 8

CSF glucose is a ____ test

Answer 8

STAT; done within 1 h of receiving in lab bc untreated bacterial meningitis is fatal!!

Question 9

glucometer

Answer 9

• finger-prick drop of blood applied to pad on strip
• increase in reflectance = increase in [glucose]
• hexokinase or glucose oxidase methodology
• dry chemistry

Question 10

a metabolic disorder characterized by the presence of hyperglycemia due to defective insulin secretion, insulin action, or both

Answer 10

diabetes mellitus (DM)

Question 11

oral glucose tolerance test

Answer 11

• may be used to test for diabetes mellitus

- measures blood glucose over 2 h after taking a load of glucose

Question 12

factors influencing the OGTT

Answer 12

• lack of standardized dietary preparation
• liver insufficiency
• chronic diseases with malnutrition
• prolonged physical inactivity
• acute stress
• endocrine diseases (Cushings syndrome)

Question 13

point-of-care teting

Answer 13

• or near patient testing

- diabetics monitor glucose to determine insulin dose; hospital use to monitor therapy adjust dosage

Question 14

glucometer

Answer 14

finger prick drop of blood applied to pad on strip
> increase in reflectance proportional to increase in [glucose]
> hexokinase of glucose oxidase methodology (‘dry chemistry’)

• whole blood glucose values ~10-15% < lab serum or plasma values
  > some machines report plasma equivalent values

Question 15

semi-quantitative methods of glucose analysis

Answer 15

• dipstick = paper strips impregnated w/ glucose oxidase
  > different chromagens or dyes
  > O-toluidine, tetramethylbenzidine
• only used for freshly voided urine; wait 10s; blue if >6 mmol/L

Question 16

false positives of dipstick test

Answer 16

due to peroxide or bleach

Question 17

false negatives of dipstick test

Answer 17

• due to ketones, ascorbic acid, salicylates

Question 18

dry or solid-phase chemistry

Answer 18

• liquid sample added to a reagent carrier cured onto a strip
• moisture of sample is solvent for enzyme rxn
• uses reflectance photometry or differential electrode methods
• no liquid waste
• no electrode maintenance, no membrane replacement
• room temp storage
• easy to use as POCT
• BUT slightly more expensive

Question 19

wet phase chemistry

Answer 19

• liquid sample added to reagents in aq solution
• follows Beer-Lambert law
• [measured substance] through absorbance
• liquid waste
• BUT requires more training to obtain good results

Question 20

consequences of DM

Answer 20

• nephropathy
• cardiovascular
• retinopathy
• amputations