Lecture 1 - Introduction to CP Flashcards Preview

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Flashcards in Lecture 1 - Introduction to CP Deck (55):
1

What 3 general things determine the quality of laboratory results

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

2

What area do 90% of mistakes occur regarding lab tests

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

3

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

pre-analytic, most errors occur here!

4

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

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

"HIT SC"

5

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

1. patient preparation

6

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

serum, plasma
clotting factors are proteins

7

purple top tube (chemical, sample, test)

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

8

green top tube (chemical, sample, test)

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

9

blue top tube (chemical, sample, test)

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

10

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

biochemical tests and most endocrinology tests

11

most labs reference samples are based on __

serum samples

12

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

EDTA

13

With EDTA contamination __ will be artifactually increased to suprephysiologic levels

potassium

14

EDTA contamination artifactually decreases __ and __

Ca and Mg

15

EDTA ___ causing a decrease in Ca and Mg

chelates divalent cations

16

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

ALP, CK, glucose, amylase, lipase

17

EDTA contamination can appear like acidosis due to __ decrease

bicarbonate (EDTA is an acid! ethylene diamineteraacetic ACID)

18

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

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

19

Best way to collect blood is by

vacutainer

20

3 direct access routes for blood sample collection

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

21

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

assisted (catheter, port, etc)

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

electrolytes will be diluted/low (Na, K, Cl)
glucose will be very high!

23

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

cool, freezing, lysis

24

old blood samples will see

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

25

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

leukocytes, MPV (mean platelet volume)

26

in old samples, cells clump and clot causing

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

27

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

MCHC (Mean cell hemoglobin concentration)

28

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

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

29

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

platelet count, MPV (mean platelet volume)

30

Aged samples result in neutrophil swelling causing a falsely interpreted

left shift/inflammatory leukogram

31

prolonged sample storage may decrease __ as glycolysis continues in vitro

glucose

32

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

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.

33

sample exposure to light degrades __

bilirubin

34

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

electrolytes

35

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

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

36

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

blood films

37

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

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

38

What analyzer value should you NEVER trust when running feline blood

automated platelet count!!!

39

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

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

40

NRBC are seen in what dz states

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

41

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

5

42

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

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

43

How do you differentiate between a nRBC and a lymphocyte?

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

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)

spectrophotometry "wet chemistry"

45

__ uses reflective photometry

dry chemistry

46

Dry chemistry results are affected by

hemolysis, icterus, lipemia, hyperproteinemia, drugs

47

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

hemolysis

48

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

K

49

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

lipemia

50

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

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

51

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

paraproteins

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)

chloride. Actually measuring the bromide with the chloride value

53

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

95% +/- 2.5%

54

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

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

55

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

64%