Lecture 1 - Introduction to CP

Question 1

What 3 general things determine the quality of laboratory results

Answer 1

1. preanalytic factors (sample quality) - patietn prep, collection tech, container, volume, handling, labeling
2. Analytic factors (analysis quality) - method, quality of equipment, quality control
3. post analytic factors (lab and patient record quality) - Min transcriptional errors, data presentation

Question 2

What area do 90% of mistakes occur regarding lab tests

Answer 2

preanalytic! mostly technical issues not patient issue
usually issues with patient prep, sample collection, container used, volume given, how sample is handled, and improper labeling

Question 3

__ phase involves all steps from test selection and sample collection to analysis.

Answer 3

pre-analytic, most errors occur here!

Question 4

What are 5 technical/non-biological factors that occur in the pre-analytic phase can cause error

Answer 4

1. test selection
2. sample tube and fill
3. sample collection
4. sample ID
5. sample handling and delayed processing

“HIT SC”

Question 5

What physicological/biological factor is in the pre-analytic phase that can be means for an error

Answer 5

1. patient preparation

Question 6

__ can clot bc clotting factors are removed where the __ will not clot bc there are clotting factors present in it.

Answer 6

serum, plasma

clotting factors are proteins

Question 7

purple top tube (chemical, sample, test)

Answer 7

chemical: EDTA
Sample: whole blood or plasma (has clotting factors)
test: CBC

Question 8

green top tube (chemical, sample, test)

Answer 8

chemical: lithium heparin
sample: whole blood or plasma (has clotting factors)
test: plasma chemistry, ammonia, CBC

Question 9

blue top tube (chemical, sample, test)

Answer 9

chemical: citrate
sample: whole blood or plasma (has clotting factors)
test: coagulation testing

Question 10

serum tubes (with (tiger top) or without (red top) separator) used for

Answer 10

biochemical tests and most endocrinology tests

Question 11

most labs reference samples are based on __

Answer 11

serum samples

Question 12

The most common mistake is ___ contamination when putting samples into tubes

Answer 12

EDTA

Question 13

With EDTA contamination __ will be artifactually increased to suprephysiologic levels

Answer 13

potassium

Question 14

EDTA contamination artifactually decreases __ and __

Answer 14

Ca and Mg

Question 15

EDTA ___ causing a decrease in Ca and Mg

Answer 15

chelates divalent cations

Question 16

EDTA contamination effects which enzyme reactions that use Ca and Mg causing decrease in these enzymes

Answer 16

ALP, CK, glucose, amylase, lipase

Question 17

EDTA contamination can appear like acidosis due to __ decrease

Answer 17

bicarbonate (EDTA is an acid! ethylene diamineteraacetic ACID)

Question 18

overall EDTA contamination can cause artifactual increase in __, decrease in __, __, __ and __

Answer 18

increased: potassium
decreased: Ca, Mg, enzymes and bicarbonate

Question 19

Best way to collect blood is by

Answer 19

vacutainer

Question 20

3 direct access routes for blood sample collection

Answer 20

1. needle, syringe
2. butterfly or extension set
3. vacutainer adapter

Question 21

__ access should be avoided to collect blood because the sample can be contaminated by IV fluids/meds and need to account for deadspace

Answer 21

assisted (catheter, port, etc)

Question 22

If a sample was taken via assisted access using a catheter where the patient was receiving fluid containing dextrose what might you see in the lab findings

Answer 22

electrolytes will be diluted/low (Na, K, Cl)

glucose will be very high!

Question 23

Sample handling: samples should be kept __ to minimize cell changes and in indirect contact with ice to prevent __ and __ of cells

Answer 23

cool, freezing, lysis

Question 24

old blood samples will see

Answer 24

lysis, RBC swelling (MCV, MCHC, PCV), crenation, and platelet activation (MPV, platelet count)

Question 25

platelet clumps are machine counted as __ and the __ will decrease __

Answer 25

leukocytes, MPV (mean platelet volume)

Question 26

in old samples, cells clump and clot causing

Answer 26

decrease in all cell types, MCV/MCHC/HCT/PVT

Question 27

RBC lysis with storage will deacrease RBC count and HCT leading to falsely high __

Answer 27

MCHC (Mean cell hemoglobin concentration)

Question 28

RBC swell with storage causing a falsely increase __ and __ and decreased __

Answer 28

MCV (mean cell volume), HCT, MCHC (mean cell hemoglobin concentration)

Question 29

platelet clumping decreases __ and increases __ since small clumps of platelets are seen as one and large clumps are not counted at all

Answer 29

platelet count, MPV (mean platelet volume)

Question 30

Aged samples result in neutrophil swelling causing a falsely interpreted

Answer 30

left shift/inflammatory leukogram

Question 31

prolonged sample storage may decrease __ as glycolysis continues in vitro

Answer 31

glucose

Question 32

prolonged sample storage may increase __ as it leaks from RBC in certain species such as __

Answer 32

potassium species with K rich RBCs: horses, Japanese dogs (Akita, shiba), camelids, pigs, sheep, some cattle. Most other dogs and cats do not show this.

Question 33

sample exposure to light degrades __

Answer 33

bilirubin

Question 34

Evaporation and freezing (sublimation = evaporation during freezing) causes falsely increased __

Answer 34

electrolytes

Question 35

When applicable, in monogastrics especially, there should be pre-analytic fasting to prevent post-prandial (after meal) __

Answer 35

lipemia. but can't fast all p (young animals, horses, cattle)

Question 36

To rule out analytic factor errors __ should always be evaluated as quality control

Answer 36

blood films

Question 37

If the analyzer gives results of thrombocytopenia, leukopenia, anemia what should you do?

Answer 37

check blood film for cell clumping (clumped cells are not read appropriately by the analyzer)

Question 38

What analyzer value should you NEVER trust when running feline blood

Answer 38

automated platelet count!!!

Question 39

__ can be counted as leukocytes by manual and some automated cell counters, need to correct leukocyte count!

Answer 39

nRBCs (metarubricytes and rubricytes) - these can be normal in low numbers for healthy dogs/cats

Question 40

NRBC are seen in what dz states

Answer 40

regenerative anemia, lead toxicity, marrow injury/dz, other inflammatory dz

Question 41

If more than __ nRBC/ 100 WBC are counted, the total WBC count will need to be corrected

Answer 41

5

Question 42

A dog has 50nRBC/100WBC with a measured WBC count of 9,000/mL. What is the corrected WBC count?

Answer 42

(measured WBC count x 100) DIVIDE (100WBC + nRBC) | (9000 x 100) / (100 + 50) = 6,000/mL

Question 43

How do you differentiate between a nRBC and a lymphocyte?

Answer 43

``` nRBC = complete rim of cytoplasm, more eosinophilic cytoplasm lymphocyte = scant cytoplasm ```

Question 44

__ is a method of absorptive photometry where reagents are added to produce a color change for biochemistry machine to observe the analytes present (lipemia, hemolysis, icterus, Ca, protein, ALP, Mg, etc)

Answer 44

spectrophotometry "wet chemistry"

Question 45

__ uses reflective photometry

Answer 45

dry chemistry

Question 46

Dry chemistry results are affected by

Answer 46

hemolysis, icterus, lipemia, hyperproteinemia, drugs

Question 47

__ can prevent correct assay results by color interference with spectrophotometric assays

Answer 47

hemolysis

Question 48

horses, cattle, some dogs have high K with RBCs so hemolysis can cause false increase in

Answer 48

K

Question 49

__ can be caused by turbidity of sample, if animal has recently eaten, or with hyperlipidemic syndromes

Answer 49

lipemia

Question 50

lipeamia can interfere with spectrophotometric assays by diluting out substances like __ resulting in falsely decreased concentrations

Answer 50

electrolytes (K, Na, Cl) = ion exclusion effect

Question 51

__ in blood due to cancer or dz effect the analytic factors by binding analytes causing hyperphosphatemia in dogs

Answer 51

paraproteins

Question 52

medications like potassium bromide can alter analytic factors causing very very high __ that is not compatible with life and negative anion gap (shouldn't be negative)

Answer 52

chloride. Actually measuring the bromide with the chloride value

Question 53

reference intervals define "normal" test results based on a median of ___ of a healthy population

Answer 53

95% +/- 2.5%

Question 54

There is a __ % chance when measuring analytes that healthy animal will return an "abnormal" test result

Answer 54

5%. Can be normal but outside of the ref interval.

Question 55

__% chance that 1 test result will be outside the reference interval when 20 analytes are measured

Answer 55

64%