MLS Clinical Chemistry Exam 1

What is a standard deviation?

the measure of the variance around a mean

how is a standard deviation useful

to termine if a value should be considered normal or not

What percent of values are found within two standard devations of the mean

95%

Why is it important to know what percentage of values are found within two standard devations of the mean

to consider whether that value should be considered normal or not

what is the coefficient of variation

a measurement of the dispersal of points around a mean

what is the formula to calcuate the coeffcient of variation for a population

SD/x-bar * 100

How does resistivity relate to the grade of reagent-grade water

the higher the grade, the higher the resistivity

T/F: ultra pure water conducts a current

F

How resistant does water need to be to be considered reagent grade

>1 megaohm

What is analytical sensitivty

how little of a compound a test can measure

what is analytical specificity

the ability of a test to correctly identify a compound amongst other compounds

What does it mean when a test has a high sensitivity

it is able to detect a compound even when there is very little of it

what does it mean when a test has a low sensitivity

it is not able to detect a compound until there is a lot of it

what does it mean when a test has high specificity

it is able to pick out a specific compound amongst several other compounds of similar structure

what does it mean when a test has low specificity

it often cross-reacts with compound it was not meant to detect but have similar structure to the desired compound

What is diagnostic sensitivity

the ability to correctly identify individuals with a disease

what is diagnostic specificity

the ability to correctly identify individuals without a disease

what is the formula for diagnostic sensitivity

TP/(TP+FN)

what is the formula for diagnostic specificity

TN/(TN+FP)

What is the purpose of a ROC curve

the determine which test has the best values of sensitivity and specificity

Which axis of a ROC curve is used to find the false-positive rate (false alarm rate)

x-axis

What does the area under the ROC tell us?

how much diagnstic ability a test has; a larger area is better diagnostic ability

What does this SPEP chart indicate

Normal

What does this SPEP chart indicate

increased alpha zones; acute inflammation

What does this SPEP chart indicate

decreased alpha 1; emphysema, lung and liver disease

What does this SPEP chart indicate

increased albumin, bridge from gamma to beta; cirrhosis

What does this SPEP chart indicate

Spike in gamma (M spike); multiple myeloma

What does this UPEP chart indicate

increased albumin, alpha 2, beta, gamma; nephrosis

What type of SPEP would be seen in polyclonal gammopathy

larger gamma diffraction with no spike

Where in an SPEP would you find albumin

albumin band

Where in an SPEP would you find antitrypsin

alpha-1 band

where would you find haptoglobin in an SPEP

beta band

where would you find transferrin in an SPEP

beta band

where would you find LDL in an SPEP

beta band

where would you find C3 in an SPEP

beta band

where would you find IgA immunoglobulin in an SPEP

gamma band

Where would you find IgG immunoglobulin in an SPEP

gamma band

Where would you find IgD immunoglobulin in an SPEP

gamma band

Where would you find IgE immunoglobulin in an SPEP

gamma band

What substances are in the gamma band of an SPEP

immunoglobluin (IgA, IgG, IgE, IgD, IgM)

Where would you find IgM immunoglobulin in an SPEP

gamma band

What types of substances would you find in the beta region of an SPEP

LDL, C3, haptoglobin, transferrin

What substances are in the alpha bands of an SPEP

antitrypsin

What substances are in the albumin band of an SPEP

albumin

Identify the test with the best overall diagnostic efficiency

PP2

What is the sensitivity of the A1c test at the given point

~72%

What is the specificity of the A1c tetst at the given point

~85%

What is the false-positive rate of the A1c test at the given point

~15%

Which point has the best combination of digagnostic sensitivity and specificity

5.6 mmol/L

What is the diagnostic sensitivity of 7.2 mmol/L

~53%

What is the diagnostic specificity of 7.2 mmol/L

>95%

What is the false positive rate of 7.2 mmol/L

What is the diagnostic sensitivity of 3.9 mmol/L

~95%

What is the diagnostic specificity of 3.9 mmol/L

~28%

What is the false positive rate of 3.9 mmol/L

~72%

What is the false positive rate of 5.6 mmol/L

28%

What does a high positive predictive value indicate

the patient is very likely to have a particular diagnosis

what does a high negative predictive value indicate

the patient is very likely to not have a partiular diagnosis

give an example of a test with a high negative predictive value

D-dimer

give an example of a test with a high positive predictive value

M-spike in gamma region of SPEP

What is the formula for the Beer-Lambert Law

A = abc

What is "A" in the Beer-Lambert Law equation

absorbance

What is "a" in the Beer-Lambert Law

the molar extinction coefficient (constant)

What is "b" in the Beer-Lambert Law

the path length of th elight transmiting cuvette (constant)

What is "c" in the Beer-Lambert Law

concentration of the sample

What is the equation to find absorbance given transmittance

A = -log(T)

What is the dynamic range

range of which the test is reliable

what is the matrix effect

using a test on a medium the test wasn't developed for; results are unusual

What Westgaurd rules are being violated here

2,4s

What Westgaurd rules are being violated here

1,3s

What pattern are these points following

trend

What Westgaurd rules are being violated here

pt 3: 1,2s; Pt. 7-10: 4,1s

What pattern are points 3-7 following

shift

What Westgaurd rule is being violated here

10x

Which part of the amino acid is the carboxyl group

red circle

Which part of the amino acid is the amine group

blue circle

What is "R"

The variable side chain

which amino acids are basic

18, 19, 20

Which amino acids are acidic

9, 10

Which amino acids are nonpolar

1, 2, 3, 4, 5, 6, 7, 8, 11

Which amino acids are polar, uncharged

12, 13, 14, 15, 16, 17

where is the amino terminal

far left, serine, 1

where is the carboxy terminal

far right, lysine, 7

Identify the peptide bonds

OC-NH bonds between amino acids

What kind of bond is this

disulfide

What are the clinical consequences in the lungs of an alpha-1-antitrypsin deficiency

there is nothing to protect the lungs from neutrophilic toxic granules

What are the clinical consequences in the liver of an alpha-1-antitrypsin deficiency

lack of antitrypsin causes misfolded proteins, liver is overwhelmed

In Maple Syrup Urine Disease, which amino acids specifically are increased

leucine, isoleucine, valine

In phenylketonuria, which metabolites are increased

toxic metabolites, exact metabolites dependent on where the block is located

in phenylketonuria, which amino acid is decreased

tyrosine

what are the clinical signs of phenylketonuria

secondary tyrosine deficiency, infants have abnormal pigmentation, mousy-smelling urine

Where is albumin synthesized

liver

where is antitrypsin synthesized

liver

where is haptoglobin synthesized

liver

where is transferrin synthesized

liver

where is LDL assembled

liver

where are immunoglobulin synthesized

Bone marrow, plasma cells, b-lymphocytes

How are most plasma proteins charged in a buffer of 7.4

negatively

which amino acids are involved in providing a charge to plasma proteins

acidic-side group amino acids

what are two physiologic functions of albumin

carries insoluble proteins/drugs, retains water through attraction of sodium