Chemistry Flashcards
function of C-peptide
distinguish exogenous from endogenous insulin
↑↑ insulin and C-peptide
insulinoma
gestational DM fasting glucose
> 95
4 criteria for DM
- A1C >6.5%
- fasting glucose >126
- 2-hour post load glucose >200
- random glucose >200 + symptoms
glycolysis reduces glucose in a sample by 5-7% per hour
solution?
separate red cells from plasma within 2 hours
sodium fluoride tube
2 main glucose methodologies
glucose oxidase
hexokinase (reference method)
CSF glucose
60-70% plasma
facilitate absorption and transport of cholesterol
micelles
the more dense the lipoprotein, the (larger/smaller) it is
smaller
“address tags” to tell the lipoprotein where to go in the body
apolipoproteins
lowest density lipoprotein
transports triglycerides from intestines
chylomicrons
lipemic plasma which separates out to a creamy layer
chylomicrons
lipemia plasma which does not separate out
VLDL
Independent, causal risk factor for atherosclerosis
Highly heritable.
lipoprotein (a)
triacyl hydrolase (lipase) + glycerophosphate oxidase
triglycerides methodology
measure HDL in samples which have been…
ultracentrifuged to remove VLDL and LDL
Friedewald formula for calculating LDL
LDL = total cholesterol - (HDL + TG/5)
cannot be used if TG >400
- ↑ waist circumference
- ↑ triglycerides
- ↓ HDL
- ↑ BP
- ↑ blood glucose
metabolic syndrome
UV, visible and infrared spectrum
UV < visible (380-750 nm) < infrared
changes the critical angle of light
solutes/particles in urine
refractometry
SG
Beer’s law
A = abc
A = absorbance
a = absorptivity
b = light path (1 cm)
c = concentration (g/L)
5 parts of a spectrophotometer
- A stable source of radiant energy
- A device that isolates a specific region of the electromagnetic spectrum
- A sample holder
- A photo detector
- A read-out device
fulminate peptic ulcers
large amounts of gastric hypersecretion
non-β-islet-cell tumors of the pancreas
Zollinger-Ellison syndrome
2 causes of PUD
- Helicobacter pylori
- NSAIDs
oral lactose tolerance test for lactase deficiency positive
unchanged blood glucose
↑ stool glucose
large amounts of serum proteins pass into the bowel lumen and ultimately into the feces
protein-losing enteropathy
transmural inflammation of the G I tract
unknown etiology
Crohn’s disease
Celiac results from a(n) ………. response to the dietary ingestion of gluten-containing grains such as wheat
inappropriate T-cell-mediated immune
Arise from enterochromaffin cells of the GI tract
well-circumscribed, round, submucosal lesions
carcinoid tumors
Gliadin antibodies (IgA & IgG)
IgA-anti-tissue transglutaminase antibody (TTG)
IgA-endomysial antibody
celiac disease tests
test for PLE
Alpha-1-antitrypsin
protein electrophoresis (↓ albumin)
↑ fasting serum gastrin
Zollinger-Ellison
Whole-body scan after oral selenohomocholyltaurine (SeHCAT)
Measurement of 7α-hydroxy-4-cholesten-3-one
Bile salt malabsorption
parts of transferrin
apotransferrin-Fe+3 complex
Iron overload without associated tissue injury
hemosiderosis
bronzing
cirrhosis
DM
hereditary hemochromatosis
serum iron + ——- = TIBC
UIBC
heme → ———— → unconjugated bilirubin
biliverdin
uridine diphosphate-glucuronyl transferase (UDPGT)
enzyme used to conjugate bilirubin
reduces conjugated bilirubin to urobilinogen and stercobilinogen
bacterial action
chalky white stool
post-hepatic jaundice
Least serious of the inherited unconjugated hyperbilirubinemia and the most common
Gilbert’s syndrome
Children are born with a decreased or absolute lack of UDP-glucuronyl transferase.
Crigler-Najjar Syndrome
most common cause of unconjugated bilirubinemia
neonatal jaundice
fatal complication of neonatal jaundice
kernicterus (neurologic damage)
Caused by 6 months to a year of moderate alcohol consumption and results in very few lab abnormalities.
alcoholic steatohepatitis
The Child-Turcotte-Pugh system is the most common.
cirrhosis staging system
Autosomal recessive disorder of copper metabolism
Kayser-Fleischer rings
Wilson disease
Jendrassik-Grof
diazo reagent
blue-green
bilirubin methodology
Berthelot reaction
Glutamate dehydrogenase
ammonia methodology
The velocity is directly proportional to the substrate concentration.
first-order kinetics
The reaction rate is independent of substrate concentration because all enzyme is saturated
zero-order kinetics
Inhibitor is structurally different than the substrate and binds to an allosteric site on the enzyme molecule.
noncompetitive inhibition
When an inhibitor binds to the E S complex to form an enzyme-substrate inhibiting complex that does not yield product.
uncompetitive inhibition
relative CK index and interpretation
RI = 100(CK-MB)/total CK
<5% —crushing injury
>5% —myocardial injury
2 > 1 > 3 > 4 > 5
LD ratios in healthy person
LD1 and LD2
heart
LD3
lungs
LD4 and LD5
liver and muscle
LD1 > LD2
MI
measure the interconversion of NAD+ to NADH at 340 nm
LD methodology
Wacker
Wroblewski
LaDue
LD methodologies
function of BNP/NTproBNP
detecting congestive heart failure
Measuring blood levels of ———- provides better risk assessment for heart disease than measuring any other biomarker.
hs-CRP
Marked elevations of —— and —— are associated with hepatocellular disease or damage to hepatocytes.
AST
ALT
Marked elevation of —— and ——- is associated with hepatobiliary disease or obstructive liver disease.
ALP
GGT
liver enzyme of little value due to lack of tissue specificity.
AST
De Ritis Ratio & interpretation
AST/ALT
> 1 —alcoholic liver disease
<1 —viral hepatitis
ALT elevation
- hepatobiliary disease
- Paget’s disease/bone disease
Distinguish using GGT; elevated in hepatobiliary disease.
Most sensitive indicator of alcoholic liver disease
GGT
Useful with ALP and GGT results in determining whether ALP elevation is from bone or liver disease.
5’-Nucleotidase (5’-NT, NTP)
increased in acute pancreatitis, obstructive liver disease, acute alcoholism, and other conditions that affect the pancreas
amylase
Maltotetraose reaction
amylase methodology
Important in screening for cystic fibrosis and chronic pancreatitis
trypsin
↑ ACP (acid phosphatase)
benign prostate hypertrophy (BPH) and prostate surgery
phosphatase used in investigating rape
ACP
Ochronosis
Darkening of the tissues of the body because of the excess homogentisic acid (alkaptonuria)
sensitive marker of poor nutritional status such as protein-energy malnutrition (PEM)
Prealbumin/Transthyretin
60% of serum protein
albumin
A/G ratio & normal
albumin/globulins
normal —1.1-2.5
In nephrotic syndrome, increased up to 10 times normal because it is retained while smaller proteins are excreted in the urine
alpha 2 macroglobulin
biuret method
total protein
Bromocresol green
Bromocresol purple
albumin methodologies
protein electrophoresis sample
serum —avoid fibrinogen peak
MM antibody classes
IgG or IgA
MM CRAB
- hypercalcemia
- renal insufficiency
- anemia
- bone lesions
Malignant proliferation of plasmacytoid cells producing IgM
Waldenstrom’s macroglobulinemia
mainly albumin in urine
glomerular proteinuria
all proteins in urine
tubular proteinuria
normal BUN:creatinine ratio
12:0 to 20:1
Berthelot’s reaction
BUN methodology
urease + Na nitroprusside
Berthelot’s reaction
BUN methodology
Nessler’s reaction
BUN methodology
Diacetyl or Fearon Reaction
BUN methodology
proportional to the muscle mass of the individual and it is released into the body fluids at a constant rate
creatinine
Jaffe reaction
alkaline picrate
creatinine methodology
major product of purine (adenine and guanine) catabolism
uric acid
Phosphotungstic acid
allantoin
uric acid methodology
creatinine clearance
CrCl = (urine conc)(urine volume in ml/min)/(plasma conc)
creatinine clearance corrected for body mass
CrCl = (UV/P)(1.73/BSA)
inability to make ammonia produces an ——— urine
alkaline
(blood is acidic)
Hamburger shift
Cl- and HCO3- “trade places” in the RBC to keep the pH correct
Henderson-Hasselbalch Equation for blood pH
pH = 6.1 + log[HCO3/(pCO2)(0.03)]
normal blood pH
7.35-7.45
normal blood HCO3
22-26 mmol/L
normal blood pCO2
35-45 mmHg
accounts for about 80% of buffering capacity
hemoglobin
acidemia (increases/reduces) Hgb affinity for O2
reduces
muscle environment
normal pO2
85-108 mmHg
↓ pH
↓ bicarb
N pCO2
uncompensated metabolic acidosis
fully compensated
pH is normal, but bicarb and CO2 are both out
blood gas sample requirements
Arterial specimen tightly stoppered
Heparinized syringe
On ice
No air bubbles
Perform ASAP
methodology using the Nernst equation
potentiometry
anion gap & normal
anion gap = (Na + K) - (Cl + HCO3)
normal —10 - 20 mEq/L
anion gap = (Na) - (Cl + HCO3)
normal —7 - 16 mEq/L
effects on boiling and freezing points as osmolality increases
Boiling point is elevated
Freezing point is depressed
calculated osmolality
mOsm/kg = 1.86(Na) + (glucose/18) + (urea/2.8) + 9
normal serum osmo
275-300 mOsm/kg
osmo gap
osmo gap = measured osmo - calculated osmo
normal — approx. 0
effects of angiogensin, aldosterone, ADH on NaCl & water
angiotensin, aldosterone: ↑ NaCl and water reabsorption
ADH: ↑ water reabsorption
effects of BNP, urodilatin on NaCl & water
inhibits reabsorption
RAAS works to ——– BP
increase
↑ ADH
↓ water output
↑ water retention
SIADH
reduces excretion of urine by reabsorbing the water back into the body
ADH
ADH deficiency
diabetes insipidus
2 types of DI
- nephrogenic —does not respond to ADH
- central —does not produce ADH
Increased urine output >2.5L/day
Urine is diluted, low specific gravity, low urine osmolality
Crave water/ice
DI
Low serum osmolality
Fluid overload (weight gain)
Hyponatremia, with continued sodium excretion
Low urine output with high specific gravity
SIADH
> 25 osmo gap
suspect ingestion of toxic substances
stimulate and promote cellular growth, differentiation, and survival
trophic hormones
used by the hypothalamus to stimulate the pituitary
releasing factor (hormone)
hormone overproduction is not suppressed by feedback inhibition
gland autonomy
used to document hyposecretion of hormones
stimulation tests
used to document hypersecretion of hormones
suppression tests
Hormonal disorder of middle-aged persons marked by elongation and enlargement of bones of the extremities and certain head bones
acromegaly
Elevated levels of GH occurring before long-bone growth is complete
pituitary gigantism
2 catecholamine-producing tumors of the adrenal gland
pheochromocytoma and neuroblastomas
↑ VMA
↑ Urinary Catecholamines
Normal Dopamine
Normal HVA
pheochromocytoma
↑ VMA
↑ Urinary Catecholamines
↑ Dopamine
↑ HVA
neuroblastoma
collection for catecholamine measurement
24 hour urine properly collected and preserved with hydrochloric acid to maintain acid pH, stored at -80°C
blood in heparin or EDTA tubes on ice, centrifuged at 4°C, plasma stored at -80°C
primary hypersecretion of hormone
main hormone ↑
tropic hormone ↓
secondary hypersecretion of hormone
main hormone ↑
tropic hormone ↑
primary adrenal hyposecretion
Addison’s disease
profound fatigue, weakness, weight loss, hypoglycemia, hyperpigmentation, hypotension, and hyperkalemia
Addison’s disease
Destructive events in the hypothalamus or pituitary gland that result in a decreased ability to secrete ACTH or CRH
secondary or tertiary adrenal hyposecretion
Cosyntropin Synacthen
used in ACTH stimulation tests
Assesses the pituitary reserve and is useful for differential diagnosis of adrenal insufficiency
Metyrapone Stimulation
secondary adrenal hypersecretion
Pituitary is stimulated to release increased amounts of ACTH
Cushing’s disease
primary adrenal hypersecretion
Elevated levels of cortisol due to either medications or the presence of an adrenal tumor (adrenal adenoma)
Cushing’s syndrome
17-OHCS test (urine)
Cushing’s
Dexamethasone Suppression Test
Cushing’s
adrenal hyperplasia with deficient synthesis of cortisol
Congenital Adrenal Hyperplasia (CAH)
Two main causes of autonomous hypersecretion of aldosterone
Conn’s syndrome
Idiopathic hyperaldosteronism
most reliable way to diagnose primary hyperaldosteronism
Adrenal bilateral vein catheterization and measuring serum aldosterone
Moonface
Buffalo Hump
Facial acne
Hirsutism
Purple Abdominal Striae
Bruises and petechiae
Osteoporosis
Edema
Thin skin
Cushing’s
deficiency of GnRH during embryonic development in both males and females. Characterized by hypogonadism and lost sense of smell (anosmia).
Kallman’s syndrome
XXY chromosomes (47 karyotype), infertile, small testicles, sparse facial and body hair, reduced muscle mass, and enlarged breasts
Klinefelter’s syndrome
55 X karyotype
Turner’s syndrome
46 XX or XY karyotype
pure gonadal dysgenesis
infertility, hirsutism, obesity, irregular vaginal bleeding, and acanthosis nigricans
PCOS
Molar tissue is a developmental anomaly of the placenta that has the potential for malignant growth
hydatidiform mole
LH:FSH ratio >2:1
no menstural cycle
PCOS
no estrogen
increased LSH and FSH
menopause
most common cause of hypothyroidism
Hashimoto’s
most common cause of hyperthyroidism
Grave’s disease
Exophthalmic eye (Eye bulging)
Tremors
Weight Loss
Graves’ disease
thyroid peroxidase +
Hashimoto’s
thyroid receptor antibody +
Grave’s disease
goiter
Hashimoto’s
phylloquinone
vitamin K assay
Beriberi, Wernicke-Korsakoff syndrome
B1 (thiamine) deficiency
Pellagra
B3 (niacin) deficiency
Rickets
vitamin D deficiency
PTH and vitamin D3 —– serum iCa and —— Phos
↑
↓
should be measured with iCa
pH; inverse relationship
sample for intraoperative PTH
K3-EDTA
CEA
GI, pancreatic, lung, breast malignancies
CA 15-3
breast, ovarian malignancy
CA 549
breast malignancy
CA 27.29
breast malignancy
CA 125
ovarian malignancy
CA 19-9
GI, pancreatic, hepatic malignancies
CA 242
GI, pancreatic malignancies
protooncogene p53
breast, colorectal, lung, liver malignancies
therapeutic drugs run on WB
Cyclosporine & Tacrolimus
Structural analog of phenobarbital
primidone
major metabolite is NAPA
procainamide
Alkaloid obtained from the bark of the cinchona tree
quinidine
signs of adulterated urine
- pH <3 or ≥11
- Nitrite concentration ≥ 500 ug/mL
- Presence of chromium (VI)
- The presence of halogens (bleach, iodine, fluoride)
- The presence of glutaraldehyde
- The presence of pyridine (pyridinium chlorochromate)
- The presence of a surfactant
- The presence of any other adulterant not specified in 3-7 is verified using an initial test on the first aliquot and a different confirmatory test on the second aliquot
Not useful if the time of ingestion is unknown or unreliable
acetaminophen levels
Can cause…
Respiratory alkalosis
Uncompensated respiratory acidosis
Metabolic acidosis
salicylate poisoning
Represent the most widely prescribed drugs due to their principal pharmacological effects
benzos
Qualitative screening test in urine is designed to detect the metabolite benzoylecgonine
cocaine
Causes miosis or constriction of the pupils in most patients
methadone
Current biomarker for assessment is venous whole blood with or without measured fluorinated ethylene propylene (FEP).
lead
Competes with ethanol for alcohol dehydrogenase (ADH)
methanol
Calcium oxalate crystals in the urine
Increase in osmol gap
Increase in anion gap
ethylene glycol
measure serum butyrylcholinesterase (pseudocholinesterase) activity to diagnose acute ingestion or monitoring chronic exposure
Organophosphate and Carbamate Compounds
% CV =
100(SD)/mean
RCF =
(1.118 x 10^-5)(r)(rpm)^2
two etched rings at the top
blowout step on pipette
1 gallon = ——— liters
3.79