Lab Statistics / Lab safety

Best indicator of precision

CV

How many % of the value fall under 1SD, 2SD, 3SD

1SD = 68.2%

2SD = 95.5%

3SD = 99.7%

To verify a reference interval, how many individuals do you need? How much percent must it (the values out of range) be to accept it

At least 20 individuals; <=10%

To establish a reference interval, how many individuals do you need? How can you set the reference range?

At least 120 individuals; Get mean and +- with the SD

Test that compares means of 2 groups; measures accuracy of 2 methods

t test

Test that compares the SD of 2 groups of data; measures precision

F test

HAXIS (term to remember the content of the graph for X-axis)

Horizontal

Abscissa

X-axis/Linear

Independent

Standard

Screening tests must have better Analytical Sensitivity or Analytical Specificity

Analytical sensitivity

Ability of a test to detect a given disease or condition; proportion of individuals with the disease who have a positive result

Diagnostic sensitivity

Probability that a positive test result indicates disease; proportion of individuals with a positive result who truly have the disease

PPV

% sensitivity formula

TP / TP + FN

% specificity formula

TN / TN + FP

PPV formula

(TP / TP + FP) x 100

NPV formula

(TN / TN + FN) x 100

Most effective control

Elimination

Least effective control

PPE

SDS has how many sections

16 sections

Standard needle gauge for routine venipuncture on patients with normal veins

21; green

Needle length for veni

1-1.5 in

Identify the glass material for tubes:

• tolerates heating and sterilization for lengthy periods; subject to scratching and may cloud with strong alkali

Borosilicate (Pyrex, Kimax)

Identify the glass material for tubes:

• 6x stronger than Borosilicate

Aluminosilicate (Corex)

Identify the glass material for tubes:

• heat, chemical, electric tolerance; pang extreme

High silica (Vycor)

Identify the pipette design:

• holds but does NOT deliver the exact volume

To contain (TC)

Identify the pipette design:

• delivers the exact volume it holds

To deliver (TD)

A blow out pipette is identified how?

Etched ring near the mouth

Identify the pipette:

• for viscous fluids

Oswalf-Folin

Between a serologic and mohr pipette, which has graduations down to the tip

Serologic

Since Mohr pipette does not have graduations to the tip, how much volume is there from the tip to the first graduation?

1mL

Semi-automated pipettes are checked when

Every 6 months

QC for centrifuge in CC

Every 3 months