Clinical Chemistry Part 1.1 Flashcards

Basic Principles to Laboratory Statistics

1
Q

What is the prefix and symbol for the following?

a. 10^1
b. 10^-1
c. 10^-2
d. 10^-3

A

a. deka (da)
b. deci (d)
c. centi (c)
d. milli (m)

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2
Q

What is the prefix and symbol for the following?

a. 10^-6
b. 10^-9
c. 10^-12
d. 10^-15

A

a. micro (u)
b. nano (n)
c. Pico (P)
d. femto (f)

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3
Q

What are the commonly used prefixes in expressing analyte concentrations?

A

milli, micro, nano, and pico

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4
Q

What is the prefix used in expressing the Mean Corpuscular Volume (MCV)?

A

femto

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5
Q

Convert. 1.0 L to uL.

A

1,000,000 uL

Note:
- L is a basic unit (including meter and gram), so the factor is 10^0.
- u has a factor of 10^6.
- To convert larger unit to smaller unit, get the difference of the exponents and move decimal to the right.
- If smaller unit to larger unit, move decimal to the left.

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6
Q

Convert 5mL to uL.

A

5,000 uL

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7
Q

Convert 5.3 mL to dL.

A

0.053 dL

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8
Q

Convert 200 uL to mL.

A

0.2 mL

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9
Q

Convert 0.00005 ng to pg.

A

0.5 pg

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10
Q

2500 pmol to mmol.

A

0.000002500 or 0.0000025

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11
Q

0.4 um to m

A

0.0000004

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12
Q

moles per L of solution

A

Molarity

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13
Q

moles per kg solvent

A

Molality

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14
Q

equivalent weights per L of solution

A

Normality

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15
Q

the amount of solute per 100 total units of solution

A

% w/v

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16
Q

volume of sample divided by total volume of solution; expression of relative concentration

A

Dilution

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17
Q

amount of something relative to
another; expressed as part per part or part per whole

A

Ratio

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18
Q

What is the conversion factor for the following analyte?

mg/dL to mmol/L

a. Glucose
b. Urea
c. BUN
d. Uric acid

A

a. 0.0555
b. 0.167
c. 0.357
d. 0.0595

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19
Q

What is the conversion factor for the following analyte?

mg/dL to mmol/L

a. Cholesterol, HDL-C, LDL-C
b. Triglyceride
c. Calcium
d. Magnesium

A

a. 0.026
b. 0.0113
c. 0.25
d. 0.417

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20
Q

What is the conversion factor for the following analyte?

mg/dL to mmol/L

a. Phosphorus
b. Lactate

A

a. 0.323
b. 0.111

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21
Q

What is the conversion factor for the following analyte?

mEq/dL to mmol/L

a. Ca2+, Mg2+
b. Na+, K+, Cl-, HCO3-

A

a. 0.5
b. 1

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22
Q

What is the conversion factor for the following analyte?

mg/dL to umol/L

a. Creatinine
b. Bilirubin

A

a. 88.4
b. 17.1

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23
Q

What is the conversion factor for the following analyte?

ug/dL to umol/L

a. Ammonia
b. Iron
c. Cortisol

A

a. 0.588
b. 0.179
c. 0.0276

24
Q

What is the conversion factor for the following analyte?

ug/dL to nmol/L

a. T4
b. T3
c. Folic Acid

A

a. 12.9
b. 0.0154
c. 2.27

25
Q

What is the conversion factor for the following analyte?

pg/dL to pmol/L

a. Vitamin B12

A

a. 0.738

26
Q

What is the conversion factor for Proteins (TPAG), g/dL to g/L?

A

10

27
Q

known as the nitrogen content of urea

A

BUN

28
Q

average or arithmetic mean

A

Mean

29
Q

midpoint of a data set after the values have been RANK-ORDERED

A

Median

30
Q

midpoint of a data set after the values have been RANK-ORDERED

A

Median

31
Q

most frequently occurring value in a data set

A

Mode

32
Q

What are the measures of central tendency?

A

mean, median, mode

33
Q

distribution of data points around the mean

A

Standard Deviation (s)

34
Q

Summation of the squares of the differences between the mean and its
observation divided by the total number of observations minus one
degree of freedom.

A

Variance (s^2)

35
Q

best indicator of precision; expressed in percent

A

Coefficient of Variation (CV)

36
Q

difference between the highest and lowest values in a data set; most unreliable when outliers are present

A

Range

37
Q

What are the measures of distribution/spread/variability?

A

standard deviation, variance, coefficient of variation, range

38
Q

Values that deviate greatly from the mean

A

Outliers

39
Q

What is the relation between CV and precision?

A

They are inversely related, in which high precision equates to low CV. The lower the CV, the higher the precision.

40
Q

What is the empirical rule in Gaussian or Normal Distribution?

A

68-95-99.7

Note:
- 68% of the values fall in +/- 1 SD
- 95% of the values fall in +/- 2 SD
- 99.7% of the values fall in +/- 3 SD

41
Q

When verifying a reference interval, at least _____ study individuals are required; RI is adopted if _____ of the subjects fall outside the range.

A

20; less than or equal 10%

42
Q

What do we do if there is no existing reference interval for an analyte or when transference studies fail?

A

establish a reference interval

43
Q

In establishing a reference interval at least ______ study individuals are required.

A

120

44
Q

→ First step in method evaluation; usually done by running two controls materials twice a day over a 10-day period.
→ Also known as 2x2x10

A

Precision Study

45
Q

→ Involves spiking a sample with a known amount of an analyte and determining how much of it can be detected by the method in presence of another compound in the matrix.

A

Recovery Study

46
Q

Compares the means of two groups of data or the accuracy of the two methods.

A

T-test

47
Q

Compares the standard deviation of two groups of data or the precision of two methods.

A

F-test

48
Q

→ Used to compare two methods using the best fit line through the data points.
→ X = independent variable/ reference method
→ Y = dependent variable/ new method

A

Linear regression

49
Q

→ Ability of a method to detect the smallest concentration of an analyte.
→ Not prone to false negative; desired in screening test

A

Analytical Sensitivity

50
Q

→ Ability of a method to detect only the analyte of interest.
→ Not prone to false positive; desired in confirmatory test

A

Analytical specificity

51
Q

Ability to detect the presence of a given disease or condition.

A

Diagnostic Sensitivity

52
Q

Ability to detect the absence of a given disease or condition.

A

Diagnostic Specificity

53
Q

Probability that a positive result indicates disease or presence of a
disease or condition.

A

Positive Predictive Value

54
Q

Probability that a negative result indicates absence of a disease or condition

A

Negative Predictive Value

55
Q

PPV, NPV, Specificity, Sensitivity Problems (see link)

A

https://drive.google.com/file/d/1-dXEKR8Z3-b8f75xuOjcOFiSv5tHVwj9/view?usp=sharing

56
Q

It is important to know and understand the clinical implications of the sensitivity and
specificity of diagnostic tests. The Prostate Specific Antigen (PSA) is one example. This
test has a sensitivity of 86% but a specificity of only 33%. What is the implication of
having these results?

A

https://drive.google.com/file/d/12JIQ10I3s4K1KmY89N806ZmyOszVHmP5/view?usp=sharing

57
Q

What is the implication of having an 80% Positive Predictive Value and a 70% Negative
Predictive Value?

A

https://drive.google.com/file/d/12JIQ10I3s4K1KmY89N806ZmyOszVHmP5/view?usp=sharing