Lab Flashcards
(168 cards)
1
Q
identify what this blood tube is
A
serum tube
2
Q
what is found within serum tubes?
A
CAT beads
3
Q
what is the role of CAT beads in serum tubes?
A
encourage clotting to occur faster
makes sample more stable
4
Q
what are serum tubes used for?
A
biochem
hormonal assays
serology
5
Q
what are you assessing during serology?
A
antibodies
6
Q
identify what this blood tube is
A
lithium heparin
7
Q
what is the role of heparin tubes?
A
biochem in house
8
Q
what is the benefit of heparin tubes?
A
tests can be run straight away
9
Q
why can tests on blood in a heparin tube be run straight away?
A
anticoagulant present
10
Q
identify this blood tube
A
EDTA
11
Q
what are EDTA tubes used for?
A
haematology
12
Q
identify this tube
A
citrate
13
Q
what are citrate tubes used for?
A
coagulation profiles
14
Q
identify these tubes
A
oxalate
15
Q
what are oxalate tubes used for?
A
glucose - rare thanks to glucometers
16
Q
what is the difference between serum and plasma?
A
serum has been allowed to clot on it’s own so contains no clotting factors as they have been used
17
Q
why does plasma contain clotting factors?
A
collected in tubes that contain anticoagulant - no clotting factors used
18
Q
does serum or plasma contain clotting factors?
A
plasma
19
Q
what tubes contain anti-coagulant?
A
heparin
EDTA
citrate
oxalate
20
Q
what order should tubes be filled?
A
serum
heparin
EDTA
21
Q
what tube must be filled last?
A
EDTA
22
Q
why must EDTA be filled last?
A
binds calcium
23
Q
why is calcium binding of benefit in EDTA tubes?
A
prevents clotting
24
Q
what results are seen on EDTA contamination of biochem samples?
A
low calcium
high potassium
25
why is high potassium seen with EDTA contamination of biochem?
2 molecules of K+ attached to each EDTA molecule
26
why are heparin tubes of benefit for emergency patients?
can be used to run tests immediately
27
what do reference ranges include?
95% of healthy animals
28
why doe reference ranges only include 95% of healthy animals?
top and bottom 2.5% disregarded as not representative of population as a whole
29
what is low total protein known as?
hypoproteinaemia
30
how is a deviation from the reference range defined as mild?
within the 'window' of the reference range
if ref range is 20, 20 above or below is 'mild'
31
how is a deviation from the reference range defined as moderate?
outside or up to double the 'window' of the reference range
if ref range is 20, 20-40 above or below is 'moderate'
32
how is a deviation from the reference range defined as marked?
3-4x the 'window' of the reference range
if ref range is 20, more than 40 above or below is 'marked'
33
what is hypoalbuminaemia?
low albumin
34
make sure you practice some reference ranges
ok!!
35
what does ALT stand for?
alanine aminotransferase
36
what does ALP stand for?
alkaline phosphatase
37
what does GGT stand for?
Gamma-glutmyl transferase
38
what is hyperbilirubinaemia?
high bilirubin within the blood
39
what is hypocholesterolaemia?
low cholesterol within the blood
40
what is low calcium?
hypocalcaemia
41
what are the main causes of high ALT?
primary hepatopathy
secondary to cholestasis
artefact
due to muscle damage
42
what is cholestasis?
bile not moving as it should out of the GB
43
how can a patient with elevated ALT be checked to see if it is muscle related?
check CK as muscle specific
44
what are the markers of hepatocellular damage?
ALT
AST
GLDH
SDH
45
what is indicated by ALT, AST, GLDH, SDH?
hepatocellular damage
46
what is occuring during hepatocellular damage?
cells leaking hepatic enzymes
47
what are the markers of cholestasis?
ALP
GGT
48
what is indicated by ALP and GGT?
cholestasis
49
what are the 2 types of liver function marker?
substances produced in the liver
substances conjugated and excreted by the liver
50
what substances are produced in the liver that can be used to measure function?
cholesterol
urea
glucose
albumin
some globulins
coagulation factors
51
what substances are conjugated and excreted by the liver that can be used to measure function?
bile acids
bilirubin
52
what can cause primary hepatocellular disease?
trauma
toxins
drugs
inflammation/infection
neoplasia
intrahepatic cholestasis
bile toxicity
53
what are the secondary causes of hepatocellular disease?
non-specific
many!!
liver is sensitive soul
54
what indicates primary causes of decreased hepatic function?
functional changes: increased levels of substances excreted and decreased levels of substances produced
55
what may increase if decreased hepatic function is seen?
bilirubin
bile acids
- should be excreted but liver can't
56
what may decrease if decreased hepatic function seen?
albumin
cholesterol
urea
glucose
clotting factors
- should be being made but liver can't
57
how can xylitol toxicity be treated?
plasma transfusions to increase protein levels
vitamin K to support clotting factor formation
IVFT to clear toxins and support BP
antibiotics as immunocompromised due to reduced globulin
58
what complications can be seen with xylitol poisoning?
DIC
59
what are the signs seen with a classic stress leukogram?
neutrophilia
monocytosis
lymphopenia
eosinopenia
60
what does SMILED mean?!
Segmented neutrophils and Monocytes Increase
Lympocytes and Eosinophils Decrease
61
are all 4 components of the stress leukogram always seen?
no - 2-3 common
monocytosis v rare
62
what is an acanthocyte?
changes to RBC cell membrane causing fingerlike projections
63
where are acanthocytes seen?
old blood
artefact
toxin ingestion
64
why can mild electrolyte changes be so concerning?
even small changes can affect physiology (e.g. K+) and have catastrophic effects (e.g. bradycardia or arrest)
65
what tests may be sued if azotemia is seen?
urinalysis
US
66
what is hypersthenuria?
concentrated urine
67
what is hyposthenuria?
dilute urine
68
what is isosthenuria?
same SG as blood - kidneys not working
69
what urine concentration is seen in kidney disease?
isosthenuria
70
what may be seen on urinalysis that indicates AKI?
inappropriate urine conc
glucose
tubular casts
71
how is ethylene glycol toxicity treated?
IVFT
supportive care
ethanol
72
what is caused by ethylene glycol ingestion?
AKI
73
what can be indicated by absence of stress leukogram?
chronic disease
immunosuppression
BM disease
74
what is liver prone to on biochem?
secondary enzyme elevations
75
how can you tell if secondary liver enzyme elevation has occurred?
GGT and ALP normal
76
what must lab findings be used in conjunction with?
clinical signs
77
what must be considered when assessing what blood results are clinically significant?
reference interval
species
significance of parameter itself
magnitude of change
clinical history
78
what is the purpose of cytology?
screening test to look for cells in fluid and tissue samples
79
where may fluid be acquired from for cytology?
BAL
CSF
synovial fluid
body cavities
80
where may tissue samples be acquired from for cytology?
lumps
bumps
lymph nodes
81
what clinical information is critical when assessing a lesion that cytology will be performed on?
clinical history
lesion evolution over days/weeks/months
previous treatment
characteristics of the lesion itself
82
how can lesions be characterised?
location
are they firm / soft
dimensions
painful or non/painful
ulceration present
depth (cutaneous or subcutaneous)
adherent or non-adherent
how aspirate appears
83
what are the 2 techniques for FNA?
suction
non-suction
84
what is suction FNA used for?
hard cutaneous or subcutaneous masses
bone lesions
non-suction technique unsuccessful
85
what is non-suction FNA used for?
soft cutaneous or subcutaneous masses
lymph nodes
vascular lesions/organs
86
describe how to perform suction FNA
negative pressure applied to syringe and needle while needle is redirected within the mass
pressure relaxed before needle removed
87
when applying negative pressure for suction FNA what should happen before the needle is removed?
pressure/suction relaxed before needle removed
88
describe how to perform non-suction FNA
needle dug around in tissue without syringe attached
needle is removed
air placed in syringe and then needle attached
air used to put sample onto slide
89
what are the main smear techniques for slide preparation?
line
squash
twist
spatter (not ideal!)
90
how is the squash technique of slide preparation performed?
using two slides placed against each other spread from the frosted edge upwards
be gentle so that cells are not crushed
91
aside from FNA what are other collection methods for cytology samples?
impression smear
scrape
imprint biopsy
imprint through rolling cotton bud for ear samples
92
what can be assessed when using a skin scape sample?
mites
93
what organism is commonly seen on ear cytology?
malassezia
94
what organism is malassezia?
fungus - yeast
95
what organism is seen here?
malassezia (yeast)
96
is malassezia seen on normal skin?
yes in low numbers
97
what indicates malassezia infection?
multiple organisms per HPF
98
how should cytology slides be dried?
quickly - hairdryer on cool or air fixation
99
what must be done with cytology slides before staining and packing?
ensure they are completely dry
100
what should all slides be labelled with?
patient ID
site
date
101
what is the most common staining technique used in practice?
Diff-Quick
102
what are some stains used in commercial labs?
Giemsa/Modified Wright
Methylene blue
Toluidine blue
ziehl/Nielson
103
what is Toluidine blue used to stain?
MCT samples
104
what is useful about Toludine blue for MCT staining?
histamine granules show up well
105
what is Diff-Quick solution A (blue) made up from?
Methanol
106
what is Diff-Quick solution A (blue) used for?
fixation
107
what is Diff-Quick solution B (red) made up from?
Eosin
108
what is Diff-Quick solution C (purple) made up from?
Methylene blue
109
what is Diff-Quick solution B (red) used for?
Eosionophilic (base) staining
110
what is Diff-Quick solution C (purple) used for?
basophilic (acid) staining
111
why should diff quick stains be replaced regularly?
methylene blue deteriorates quickly
112
should the same Diff-Quick stains be used for all samples?
should have clean and then dirty set for dermatology
113
what cells are seen in this picture?
neutrophils
114
what power of lens is found in the eyepiece of a microscope?
10
115
what is the combined power of the eyepiece and lens on a microscope?
lens power x10 for eyepiece
116
what should be assessed on low magnification (10x)?
cellularity
preservation
staining
haemodilution
cell distribution
background
117
assess cellularity in this image
low
118
assess cellularity in this image
high
119
what is haemodilution?
RBC present in sample
120
what is the total magnification of the 40x lens?
400x human eye
121
what is assessed on the high magnification (40x) lens of a microscope?
cellular vs non-cellular elements
inflammatory vs neoplastic
malignant vs benign
122
what is assessed on the high magnification (100x) lens of a microscope?
presence of cytoplasmic granules
nuclear detail
presence of pathogens (bacteria, fungi, protozoa)
123
what indicates inflammation on cytology?
neutrophils
124
how do neutrophils appear on cytology?
clear nuclear outlines with dark purple chromatin
cytoplasm is pale and clear/slightly pink
125
what are degenerate neutrophils?
neutrophils affected by toxic change (e.g. infection)
126
how do degenerate neutrophils appear under the microscope?
loss of segmentation
lighter colored 'fluffy' nuclear chromatin and swollen appearance
127
does the absence of bacteria on a slide mean there is no infection?
no if neutrophils present - culture should be performed
128
what cells are seen in this image?
non-degenerate neutrophils
129
what cells are seen in this image?
degenerate neutrophils
130
what is seen on this slide?
MCT - many histamine granules
131
what is seen on this slide?
evidence of lymphoma
132
what is seen on this slide?
adipose tissue indicative of lymphoma
133
what are the benefits of cytology?
easy
quick
cheap
relatively non-invasive
134
what are the limitations of cytology?
screening test not confirmatory
135
what is needed to to confirm suspicions seen on cytology?
histology
136
why is QA/QC important for lab machines?
life/death/diagnostic decisions will be made based on results given so they must be correct
137
how can QA/QC be maintained?
set-up correctly
maintain analysers and systems
interpret results
carry out controls
ensure accurate record keeping
138
what are the advantages of in house labs?
fast turn around time
potential for improved patient monitoring
smaller sample volume needed
available OOH
available in remote areas
may save costs
139
what are the 2 major variations which affect results?
biological
analytical
140
what factors affect results prior to sampling?
biological
141
what are the biological variables that may affect results?
inter-individual
intra-individual
142
what are inter-individual factors?
inherent differences between groups of animals due to effects of species, breed, age and/or sex
143
what are intra-individual factors?
transient differences in the same animal
144
what are intra-individual factors due to?
environmental or external factors
145
what are some examples of intra-individual factors?
diet (recent meal)
stress/excitement
reproductive status/lactation
drugs
146
can intra-individual factors be eradicated?
no but should be minimised as much as possible
147
what are the analytical factors that can affect results?
pre-analytical
analytical
post-analytical
148
when do pre-analytical factors occur?
before the sample is run
149
what are some pre-analytical factors that may affect results?
poor sampling technique
haemolysed, lipaemic or icteric plasma
wrong anticoag to blood ratio
sterile or non-sterile container if needed
transportation
storage
150
what is a haemolysed sample?
one where RBCs have broken - plasma pink/red
151
where should samples be stored?
fridge if there is delay in testing
152
why should samples be stored in the fridge?
slows cell metabolism
153
what is the fluid limit for sending samples by post?
50ml
154
how must samples be packed for posting?
sealed container
leakproof bag
absorbative padding - enough to absorb all fluid if container breaks
packaged in rigid container
155
when do analytical factors occur?
while the test is running
156
should patient side and lab methods of blood testing be compared?
no - results vary significantly so should not be compared directly
157
what are analytical factors?
factors which cause variaton/error during the analysis of the sample and influence the final result
158
what are the 4 main analytical factors?
equipment
technician
analytical procedure
laboratory
159
is quality control a legal requirement?
no regulation just recommendations
voluntary
160
when should quality control be performed?
regularly according to manufacturer recommendations
161
what is involved in quality control?
control material of known composition is measured to check the accuracy of the analytical process as results are known
162
when is quality control performed?
during analysis to ensure validity of result
163
what should be done if a control fails?
check for obvious problems
use another tube of control materials
repeat control in full
164
what are some obvious reasons for control fails?
reagent depletion / expiry
mechanical faults
clots - machine clean
165
once a repeat control has been tried and it fails what should be done?
use new lot of reagent, re-calibrate and repeat control
then run routine maintenance and repeat control
consult manufacturer
166
when do post analytical factors occur?
after sample is run
167
what are some examples of post analytical factors?
incorrect transfer of results to the patient record
results not archived correctly
storing the specimen incorrectly / not storing for additional tests
168
what are the main ways to ensure QA/QC?
best sample possible
stick to maintainance routines
don't use old reagents
check if results don't make sense
