exam 4 Flashcards by whitney webb

what is the substance for the enzyme aspartate amino transferase (AST)

aspartate

alpha ketoglutamic acid

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creatinine is formed from the breakdown of what

creatine

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PSP is removed from the blood by what

kidneys

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what is the principle of the Berthelot reaction and what substances can cause falsely elevated values in the reaction?

hydrolysis of urea to ammonium carbonate by enzyme urease ammonia. ammonium reacts with phenol and sodium hypochlorite to form a BLUE colored indophenol. Sodium nitroprusside serves as the catalyst

ammonium, lipemia, icteric specimens

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increased ALT values are associated with dieases of the what

liver

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what is the normal values for serum AST at 37 C

5-35 IU/L

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which anticoagulant should NOT be used for urease testing?

sodium fluoride

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what is the normal percentage for the CK-MB isoenzyme?

less than 6%

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what reagent is used in the measurement of uric acid?

phosphotungstic acid

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creatinine clearance is used to assess the rate of what

glomerular filtration

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creatinine clearance formula

CrCl= (UaVu) / (PaT)

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what additional information must be known for the CrCl formula if the patient is a infant, young child, or adolescent

body surface area

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what is the most common endogenous substance used to assess the glomerular filtration rate

creatinine

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what is the most common exogenous substance used to assess the glomerular filtration rate

inulin

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serum creatine kinase is most often elevated in diseases of what?

muscle tissue

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serum lipase levels are elevated in diseases of what?

pancreas

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Diacetyl Monoxime reacts with ____ to produce a yellow product.

urea

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what is uremia?

retention of urea and abnormal substances in the blood

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what is the normal value for CK in males at 37 C

15-160 IU/L

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name three ways that can be used in the laboratory to measure the rate of an enzymatic reaction and give the general term that can be applied to two of the three methods

multiple point assay
continuous monitoring method

both called kinetic

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define international unit (IU)

catalyzes one micromole (umol)/ minute of substrate

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what is the peak absorbance of reduced NAD (NADH)?

340 nm

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the jaffe reaction is used to measure what?

creatinine

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which non-protein nitrogen component compromises the largest fraction of NPN in the blood?

urea

BUN

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which enzyme is useful in the detection of insecticide poisoning?

pseudocholinesterase

low levels of which enzyme can cause a patient to be susceptible to prolonged apnea when exposed to certain types of anesthesia?

pseudocholinesterase

increased levels of LD-4 and LD-5 are associated with what?

liver/ acute hepatic disease

Gout is caused by the deposition of what in joints and other tissues

uric acid

what is the clinical significance of a mildly elevated ALP in a teenager?

no clinical significance

what is the normal ratio of BUN to creatinine?

10:1 - 15:1

what enzyme is normally elevated during pregnancy?

alkaline phosphatase

L-tartrate is used in the specific assay of which enzyme?

prostatic acid phosphatase

which isoenzyme is detectable within 4-6 hours after a MI?

CK-2 or CK-MB

retention of BSP can be used to measure what function?

liver

what substrate and coenzyme are required to measure ammonia?

alpha ketoglutarate | NADH

what is the main way that ammonia levels are kept within normal limits?

synthesis of urea in the liver

Amylase is an enzyme that breaks down what?

starch

why should hemolyzed specimens NOT be used for acid phosphatase?

RBC contain acid phosphatase levels increase

acid phosphatase is primarily associated with diseases of what

prostate

what is the proper treatment of serum to be assayed for ACP?

acidified to a pH below 6

what is the substrate for alkaline phosphatase methods of analysis?

para-nitrophenolphosphase

in the urease method, urea is converted to what?

ammonium carbonate

increased levels of serum alkaline phosphatase can indicate diseases of what?

bone or the liver

the enzyme responsible for the reversible oxidation of lactic acid to pyruvic acid is what?

LD | lactase dehydrogonase

in the creatine kinase reaction what is converted?

ATP to ADP

what is the end product or purine metabolism in man?

uric acid

serum amylase might be expected to be increased in diseases of the what?

pancreas and salivary glands

which enzyme can be used to establish the presence of semen?

acid phosphatase

phenylketonuria (PKU) results from a deficiency in which enzyme?

phenylalanine hydroxylase

what is the substrate for the enzyme alanine aminotransferase (ALT)

alanine | alpha-ketoglutamic acid

what is the source of urease used in enzymatic methods for the determination of BUN

jack bean meal

what precaution must be taken with specimens to be used for blood ammonia determinations?

avoid ammonia forming in vitro placed on ice correct tube plasma tested within 15 minutes

what is the correct order of migration of the creatine kinase (CK) isoenzymes starting with the slowest?

CK-MM CK-MB CK-BB

what is(are) the substrate(s) for amylase in the dye-labeled substrate method?

starch & dye

in the creatinine method, a color develops when creatinine combines with what

alkaline picrate

the major isoenzymes of lactate dehydrogenase come from the what?

heart and liver

what is the principle of the enzymatic method for measurement of ammonia?

change in absorbance at 340 nm uses enzyme glutamate dehydrogenase and the substrate alpha-ketoglutarate & the reaction is followed by decreased absorbance @ 340 nm as NADPH is converted to NADP

strenuous exercise can cause an elevated what

what causes the BSP dye to turn from colorless to colored?

alkali medium

what would hemolysis do to the results of a lactate dehydrogenase (LD) measurement?

elevates results

how are the results of LD measurement affected if the specimen is frozen?

falsely decreased

what test can differentiate between liver and bone origin of an elevated alkaline phosphatase?

GGT

what is the best anticoagulant to use for plasma specimens to be tested for LD

heparin

what is the order of migration for the isoenzymes of alkaline phosphatase

liver fastest bone placenta intestinal

what is the characteristic change in the isoenzyme of LD that is seen in MI?

LD 1 is greater than LD 2

creatinine excretion correlates best with what

muscle mass

which enzyme is the first to become elevated following a MI?

CK-MB

aspartate amino transferase is elevated in diseases of what

heart

for how long and at what temperature should specimens for LD be stored

2-3 days at room temperature

in the performance of a creatinine clearance, when should the specimen for serum creatinine be collected in relation to the collection of the urine?

midway through urine collection NOT longer than 24 hours before or after collection

what enzyme can be used in the detection of alcoholism and in the monitoring of patients in alcohol treatment centers

GGT

what is the normal value for prostatic acid phosphatase

less than 2.1 ng/ml

why are creatinine levels in the serum not a good indicator of early renal damage?

values are not above the upper limit of normal until 1/2 to 2/3 of renal function is abnormal

what is the composition of Nessler's reagent and for what test is it used?

double iodide of potassium/mercury BUN

which has more liver specificity, alanine aminotrasnferase (ALT) or aspirate amintoranferase (AST)

ALT is more specific | AST is for the heart

in which organs is the activity of creatine kinase (CK) the greatest

brain heart skeletal muscle

what is the main factor that determines how much the level of an enzyme in serum increases?

extent | severity of damage to its tissues or cells of origin

how does progressive muscular dystrophy affect AST and ALT levels

increases AST and ALT levels

what is the normal value for serum amylase at 37C

95-290 IU/L

what is the major creatinine kinase isoenzyme of normal serum?

CK-MM

at what temperature should serum CK specimens be stored?

4C refrigerated

what is the purpose of the PSP test and the p-aminohippurate test

measure excretory capacity of the kidneys

to what class of enzyme do amylase and lipase belong

hydrolase

what is the normal value for serum BUN

8-26 mg/dl

what is the old name for AST

SGOT | serum glutamic oxaloacetic transaminase

what is the old name for CK

CPK | creatine phosphokinase

what two isoforms of CK are used for the early detection of an MI

CK-MM | CK-MB

what is the main use of ammonia measurements

diagnose Reye's syndrome | hepatic coma

what happens to the creatinine clearance value in renal disease

decreases

What is the normal range for total serum bilirubin?

0.2-1.0 mg%

In the Jendrassik-Grof method, what is the caffeine benzoate solubilizer used for?

Solubilizes the water-insoluble fraction of bilirubin and will yield a total bilirubin value. Without it, the rxn will yield conjugated bilirubin only

A list of risk factors for coronary heart disease

``` Smoking Hypertension Increased total cholesterol & LDL Decreased HDL Diabetes mellitus Age Obesity Physical Inactivity Family history of premature CHD Left ventricular hypertrophy ```

List of biochemical markers for coronary heart disease

Triglycerides Lp(a) Homocysteine hs-CRP

List of the ideal characteristics of a cardiac marker

``` Cardiac specific Rises soon after infarction occurs Elevated over a sustained period of time Easy to measure analytically Broad dynamic range for measurements Quick turnaround of tests Diagnostic utility verified by clinical studies ```

Which marker has been recognized for the earliest biochemical marker for AMI?

Myoglobin

What is the biggest disadvantage of troponin as a cardiac marker?

Remains in blood 7-10 days (can't detect new infarction within that time frame)

What is the most likely cause of prehepatic bilirubin?

Increased amount of bilirubin being presented to the liver, such as in acute or chronic hemolytic anemias

Why are high levels of bilirubin seen in infants?

infant deficiency of enzyme glucuronyl transferase (last to develop because most bili processing done by mother)

What precautions need to be taken when processing bilirubin?

Serum or plasma (except in Malloy-Evelyn, use serum) Fasting specimen preferred Hemolysis not acceptable Keep away from light Stable 2 days at RT, 1 week at 4C, indefinitely at -20C