Lab

Question 1

What method was used in the lab to measure total protein?

Answer 1

Biuret method

Question 2

What does the biuret method consist of?

Answer 2

Copper sulfate reacting with peptide bonds with increasing intensity to their concentration. Colored chelate forms with amine nitrogen of the peptide bond with an absorbance at 540nm.

Question 3

What type of amino acids react with the biuret method?

Answer 3

Tripeptides and polypeptides. Dipeptides or single amino acids do not.

Question 4

What is intensity of color in biuret method results proportional to?

Answer 4

Number of peptide bonds and therefore protein concentration

Question 5

Identify the other methods for assessing total protein.

Answer 5

Kjehldahl
Refractometry
UV absorption

Question 6

What method is used for detecting albumin?

Answer 6

Dye binding technique

Question 7

How does the dye binding technique work?

Answer 7

In dye binding technique, anionic dye binds to albumin at a pH of 4.2, pH at which albumin is cationic. BCG binds specifically to albumin although it will bind other plasma proteins over time. BCG binds to protonated amine groups on the albumin molecule and the complex forms a color at 550-630 nm

Question 8

What type of specimens are used for total protein albumin measurements?

Answer 8

Serum
Heparinized plasma
Body fluids/urine

Question 9

What is the reference interval for total protein?

Answer 9

6.5-8.3 g/dL

Question 10

What is the reference interval for albumin?

Answer 10

3.5-5.5 g/dL

Question 11

What is automation?

Answer 11

The mechanization of chemical analyses done in order to minimize manual manipulation

Question 12

List the steps in the automated process

Answer 12

Separation/mixing
Sample/reagent handling
Incubation
Reaction and reaction analysis
Derivation/interpretation of results
Result reporting

Question 13

What are the advantages of automation?

Answer 13

Time saving
Removes human performance variability
Reduces error
Saves money

Question 14

What are the disadvantages of automation?

Answer 14

High initial/startup cost
Discontinued or updated products and reagents
Special training required

Question 15

What are discrete analyzers?

Answer 15

Analyzers in which samples and reagents are mixed and react in individual cucette or slide

Question 16

What are continuous flow analyzers?

Answer 16

Analyzers in which sample is injected into a reagent stream and reactions take place in tubing

Question 17

What can be a major problem with continuous flow analyzers?

Answer 17

Carryover

Question 18

How does sample processing with batch analyzers work?

Answer 18

Only one analysis is performed on a single specimen at a time or many specimens are sequentially moved through the analyzer as one batch

Question 19

How does random access analyzers work?

Answer 19

Operators can program a number of tests, profiles/panels, QC on any given specimen in any order. Many analyses can be performed on a single specimen before moving on to the next sample

Question 20

What is the most common system of analyzers?

Answer 20

Random access analyzers

Question 21

What are calibrators or standards?

Answer 21

These are substances of known concentration run initially to create a standard curve

Question 22

How many cakibartions are there?

Answer 22

One calibration per analyte

Question 23

What are unknowns comapred to?

Answer 23

Standards on the curve once validated through calibration and QC

Question 24

What are controls?

Answer 24

Substances of a known general range run daily or per shift to confirm system validity through QC

Question 25

What us a substance with a specific known concentration?

Answer 25

Standard/calibrator

Question 26

What is a substance similar to patient samples that has a known set of ranges? Usually pooled serum or plasma

Answer 26

Control

Question 27

What substance tests an instrument to ensure that accuracy and precision of the equipment in order to validate the reliability of the system?

Answer 27

Control

Question 28

What substance is used to setup an instrument, setting up a measuring scale to compare unknowns to

Answer 28

Calibrator/standard

Question 29

How often are standards run?

Answer 29

Occasionally like after a new instrument install

Question 30

On how many levels are standards run?

Answer 30

They’re run on multiple levels to get a multipoint calibration

Question 31

Hi How often are controls run?

Answer 31

They’re ran as a patient is tested everyday or per shift.

Question 32

On how many levels are controls run?

Answer 32

Run on multiple levels to test both normal and abnormal range reliability. When 3 levels: low abnormal, normal, high abnormal When 2 levels: normal and abnormal

Question 33

What is sensitivity?

Answer 33

It is the ability of an instrument to detect the smallest amount of an analyte

Question 34

Describe the relationship between sensitivity and concentration

Answer 34

The more sensitive a test is, the lower the concentration it can detect

Question 35

What is accuracy?

Answer 35

It is the capability of an instrument to provide a true of a quantity

Question 36

What is precision?

Answer 36

Precision is a measure of the reproducibility of an instrument. Do repeated measures give the same value no matter the accuracy?

Question 37

Define linearity

Answer 37

It is the ability of an instrument to give a constant ratio of a response to varying concentrations of stimulus when they are in direct proportion

Question 38

What is the purpose of linearity?

Answer 38

Checks out that the output reading of an instrument is linearly proportional to the quantity being measured Defines the range of the method within which the results are obtained accurately and precisely

Question 39

what are chemistry panels/profiles?

Answer 39

Variety of tests designed to assess a single system (renal, hepatic, pancreatic) or state (metabolic, lipid)

Question 40

How is LDC calculated?

Answer 40

LDL = Total CHOL - HDL - TG/5