Clinical Pathology Flashcards

1
Q

EDTA sample tubes

A
  • Haematology - preservation of cells, quantitative examination + qualitative examination (blood smear)
  • K2EDTA or NaK-EDTa
  • Fibrinogen (some labs)
  • PCR (some labs/assays, may need heparin, EDTA/heparin anticoagulant interfere w/ PCR)
  • Chelates Ca2+, Mg2+, Fe2+ -> stops clotting
  • Fluids for cyto
  • Pink tube
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2
Q

Citrate sample tube

A
  • Coagulation profile
  • Fibrinogen (some labs)
  • PT
  • APTT
  • D-dimers
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3
Q

Plain sample tubes

A
  • Biochem
  • Endocrinology
  • Serology
  • Fluids for culture - white top tubes
  • Should be at room temp 15 - 20 min until full clot formation has occurred
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4
Q

Heparin sample tube

A
  • Lithium heparin
  • Biochem (+ haematology - exotics)
  • PCR (some labs/assays)
  • Unsuitable for haematology - results in poor leucocyte staining on blood films
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5
Q

Fluoride oxalate sample tube

A
  • Glucose - prevents glycolysis/oxidation of glucose
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6
Q

When to take urine sample

A
  • Starve 8 - 12 h - eliminates effects of glucose, creatinine + cholesterol values from feeding inc
  • When clinical effects most apparent - e.g. post-seizure
  • Monitoring therapy trough/peak samples may be required
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7
Q

Factors that affect clin path

A
  • Signalment - species - diff machine settings, diff reference intervals, diff clinical decision limits, more concern if inc ALP + ALT in cats
  • Breed - e.g. greyhound (inc Hct, inc creatinine, dec T4) - variable haem, biochem + endo parameters
  • Age - haem - switch from foetal (larger blood cells) circulation; biochem - bone growth, organ development; endo - age variation - inc ALP, Ca + P in younger animals
  • Sex - hormones can influence tumour growth
  • Medications - corticosteroids -> stress leucogram; sedatives -> sequestration of populations in spleen -> enlargement, blood pooling -> dec Hct, dec WBC, lower count as in spleen; phenobarbitone -> immune-mediated neutropoenia
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8
Q
A
  • Erythrocytes
  • Inc polycythaemia = phlebotomy
  • Dec = anaemia
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9
Q
A
  • Thrombocytopoenia - < 50 units
  • Low no. -> spontaneous H+
  • Immune-mediated - extremely low platelet no.
  • Mild dec = H+
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10
Q
A
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11
Q

Toxic changes of neutrophils

A
  • Cytoplasmic change
  • Dohle bodies (light blue-gray, oval, basophilic, leukocyte inclusions located in the peripheral cytoplasm of neutrophils)
  • Foamy cytoplasm
  • Basophilic cytoplasm
  • Indicates inflam response - infection or sterile (burn or trauma)
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12
Q
A
  • Band neutrophil to metamyelocyte
  • Left shift
  • Smooth nucleus
  • Metamyelocyte = less elongated
  • Inflam response
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13
Q
A
  • Rabbit + exotics
  • HETEROPHILS (don’t have neutrophils) - granules stain much brighter
  • May observe small + large lymphocytes
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14
Q
A
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15
Q
A
  • Precursor to macrophages
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16
Q
A
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17
Q
A
  • Inc suggests autoimmune, myeloproliferative disorders - chronic myelogenous leukaemia (CML), primary myelofibrosis; inflammation; allergies; infection
  • Value usually approx 0 anyway
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18
Q

Dec RBCs

A
  • Anaemia
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19
Q

Inc RBCs

A
  • Erythrocytosis/polycythemia
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20
Q

Dec Hct/PCV

A
  • Anaemia
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21
Q

Inc Hct/PCV

A
  • Erythrocytosis/polycythemia
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22
Q

Dec MCHC

A
  • Hypochromasia
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23
Q

Inc MCHC

A
  • Hyperchromasia
  • Consider that RBC parameters inaccurate
  • IMHA - a lot of free Hb in blood, cell agglutination, don’t separate into single cells, clump together
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24
Q

Dec MCV

A
  • Microcytosis
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25
Q

Inc MCV

A
  • Macrocytosis
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26
Q

Inc RDW (red cell distribution width)

A
  • Anisocytosis
  • Regenerative response
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27
Q

Blood loss

A
  • H+
  • Haemolysis
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28
Q

Mild non-regen anaemia

A
  • PCV = 30% (dog), 20% (cat)
  • Anaemia of chronic inflam disease
  • Normocytic normochromic
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29
Q

Mod non-regen anaemia

A
  • PCV < 20%
  • Dec erythropoietin - CKD
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30
Q

Marked non-regen anaemia

A
  • PCV < 15%
  • Dec production of RBC
  • Bone marrow disease
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31
Q
A
  • Normocytic
  • Normochromic
  • Non-regenerative
  • Mild
  • Anaemia of chronic or inflammatory disease
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32
Q
A
  • Macrocytic
  • Hypochromic
  • Often regenerative
  • NB could also be in vitro storage artefact - swell + take in water
  • Polychromatocytes + leptocytes (larger, folded cells)
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33
Q
A
  • Microcytic
  • Hypochromic
  • Iron deficiency
  • Chronic external haemorrhage
  • Portosystemic shunt - alters iron met pathway
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34
Q

Serum

A
  • Plasma - clotting factors
  • Mostly heparin plasma for biochem, may have microclots in heparin
  • Obtained after leaving to clot for min 30 min
  • Less likely to contain clots that interfere w/ results
  • If separated within 2 h, analytes tend to be more stable
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35
Q

Plasma

A
  • Clotting factors - coagulants - fibrinogen
  • Plasma proteins - albumin and globulin
  • Separated + run immediately from blood sample
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36
Q

What may affect biochem results?

A
  • Haemolysis -> release of ALT + K+ from lysed RBC -> inc serum values
  • Lipaemia (inc turbidity)
  • Icterus (colour substances) -> inc bilirubin
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37
Q

Proteins

A
  • Albumin, globulins etc.
  • Most synthesised by liver
  • Maintain oncotic pressure
  • TP + albumin measurement
  • Globulin = TP - albumin
38
Q

Albumin

A
  • Smallest proteins but most common in plasma/serum
  • Synthesised in liver
  • Inc w/ dehydration, corticosteroids
  • Dec = inc loss/dec production - PLE, PLN, liver disease, negative acute phase response proteins - in inflam, dec
  • CRP + Haptoglobin positive APP inc
  • Albumin dec in inflam = NAPP
39
Q

Globulins

A
  • Inc = antigenic stimulation, neoplasia (lymphoid neoplasia, plasma cell neoplasia modified form of B cells)
  • Dec = loss, due to H+, PLE, PLN or dec production and/or inc protein catabolism
  • Synthesised in the liver
40
Q

Protein electrophoresis

A
  • Differentiate types of hyperglobulinaemia
  • Monoclonal - neoplasia
  • Polyclonal - inflam in FIP
41
Q

Urea + creatinine

A
  • Azotaemia = elevation of urea + creatinine
  • Pre-renal, renal, post-renal
  • Assess w/ hydration status of patient + USG at time of taking serum
42
Q

Pre-renal azotaemia

A
  • Dehydration / hypovolaemia
  • 2y to V+
  • High protein meal - starve for 12 h to reduce interference
  • GI H+ may result in elevations
43
Q

Post-renal azotaemia

A
  • Obstruction - full bladder, Hx stranguria
  • Ruptured bladder - post obstruction/RTA
  • Sample peritoneal fluid assess serum + fluid urea creatinine
44
Q

Renal azotaemia

A
  • Azotaemia (inc urea + inc creatinine) + isothenuric urine (USG: 1.008 - 1.012)
  • Most concerning finding
  • AKD/CKD
45
Q

Hepatocellular damage

A

Inc enzymes
- ALT
- GLDH
- SDH
- (AST/LDG)

46
Q

Cholestasis

A

Inc
- ALP
- GGT

47
Q

ALT

A
  • Alanine aminotransferase
  • Hepatocellular (present in most cells)
  • Transient inc = RTAs, liver or muscle damage, does not correspond w/ degree of damage
48
Q

ALP

A
  • Alkaline phosphatase
  • Not specific for cholestasis, but more sensitive
  • Released from brush border of bile ducts
  • Isoforms - bone (growing animals + bone path), canine - steroid-induced, gut - transient
49
Q

GGT

A
  • Gamma-glutamyl transferase
  • Specific for cholestasis + biliary tract disease, less sensitive than ALP
  • Inc in neonates - colostrum intake
  • Inc w/ steroids
50
Q

Bilirubin

A
  • Inc = pre/post/hepatic
  • Pre-hepatic = haemolysis, check HCT, inc in IMHA
  • Hepatic, post hepatic = cholestasis, unable to excrete
51
Q

Bile acids

A
  • Pre + postprandial bile acids - sample, feed, then sample 2 h post-feeding
  • Func test for liver - may be affected by enterohepatic circulation disturbances
52
Q

Ammonia

A
  • Func test for hepatocytes
  • Changes seen following air exposure
  • Need to separate EDTA plasma immediately
  • If running in-house, exposure to urea reagents may inc
53
Q

Cholesterol

A
  • Synthesised + met in liver
  • Inversely proportional to T4
  • Inc - hepatic disease, endocrine disease (hypothyroidism, hyperadrenocorticism, DM), nephrotic syndrome
  • Dec - malabsorption, hyperthyroidism (feline), liver failure, PSS, PLE
54
Q

Creatine kinase

A
  • Muscle cell leakage/damage
  • Marked - aortic thromboembolism in cats (thousands)
  • Rapid elevation + short half-life - AST has slower response but persists for longer
55
Q

Amylase + lipase

A
  • Marked elevation - pancreatitis (but may see no elevation)
  • Elevation - other pancreatic disease, dec renal clearance (2 - 3 x), GI obstruction, dexamethasone (lipase, 5 x)
  • DGGR lipase = more specific for pancreatitis than older lipase assays
56
Q

Calcium + phosphorus

A
  • Regulated by PTH - promotes Ca2+ absorption + PO4^3- excretion
  • Elevations - growing animals - bone metabolism
  • Inc Ca2+ - hypercalcemia of malignancy, check ionised calcium inc
  • PTHrP produced by several neoplasms (anal gland sac adenocarcinoma, SCC, lymphoma)
57
Q

Potassium, Sodium, Chloride

A
  • Intake from diet
  • Kidneys regulate by excretion + resorption
  • Affected by dehydration, shifts of electrolytes between ICF + ECF
  • Na + Cl move together (should be proportional)
58
Q

Glucose

A
  • Ingested or synthesised by cells
  • Maintained at constant level as glycogen, mostly in liver
  • Insulin = uptake + glycogen synthesis
  • Glucagon = glycogen breakdown
59
Q

Hyperglycaemia

A
  • Transient - stress, up to 17 mmol/L - cats + young animals
  • Persistent = diabetes mellitus
  • Inappropriate glucose supplementation
  • Hypovolaemia
  • Use fructosamine (glycosylated proteins - reflects glucose levels of previous 2 - 3 w)
60
Q

Hypoglycaemia

A
  • False reading/lab error - storage/hamolysis in-vitro, glycolysis post-collection, failure to separate from erythrocytes ASAP
  • Send in fluoride/oxalate tubes to inhibit glycolysis
  • Insulin overdose
  • Insulinoma
  • Hepatic disorder - liver tumours
  • Sepsis
  • Addison’s (hypoadrenocorticism)
61
Q

Urine specific gravity

A
  • Isothenuric = 1.007 - 1.012
  • Central diabetes insipidus
  • Or nephrogenic diabetes insipidus - pyo, sepsis, unable to respond externally, unresponsive to ADH
  • Hyposthenuric = < 1.007
    Good concentration =
  • Feline = > 1.035 (1.040)
  • Canine = > 1.030
  • Equine/large animal = > 1.020
62
Q

Sediment examination

A
63
Q

PCV

A
  • Haematocrit tube
64
Q

TP

A
  • Refractometer
65
Q

Point of care test

A
  • Blood glucose
  • Blood urea nitrogen (BUN)
  • Blood lactate
66
Q

Dec PCV; normal TP

A
  • Haemolytic anaemia
  • Aplastic anaemia
  • Pure red blood cell aplasia
  • Anaemia of chronic disease
  • Sample haemolysed - IMHA?
67
Q

Inc PCV; normal TP

A
  • Polycythemia vera
  • Hyperthyroidism
  • Cushing’s (hyperadrenocorticism)
  • Haemorrhagic gastroenteritis (HGE)
  • EPO-producing tumour (renal)
68
Q

Normal PCV; dec TP

A
  • PLE
  • PLN
  • Liver failure - lack of production of albumin
  • Acute blood loss w/ splenic contraction
  • Third spacing (fluid from the local interstitial and intravascular spaces leaks into body cavity)
69
Q

Normal PCV; inc TP

A
  • Multiple myeloma
  • FIP
  • Chronic globulin stimulation - dental disease, skin disease
  • Severe dehydration + anaemia e.g. CRF
  • Lipaemic serum
70
Q

Inc PCV; inc TP

A
  • Haemoconcentration - inc RBCs, loss of plasma - dehydration
71
Q

Dec PCV; dec TP

A
  • Chronic blood loss (melaena)
  • Blood loss - sub-acute
72
Q

Blood lactate

A
  • Inc = decreased tissue perfusion (lactate obtained from anaerobic glycolysis)
  • Raised levels should begin to fall 15 - 30 min after successful resuscitation
  • Artefacts - rise steadily due to glycolysis if samples stay in contact w/ RBCs after collection; restraint + prolonged venous occlusion
  • If samples to be submitted - use heparin/fluoride-oxalate tubes + separate plasma from RBCs within 5 min
73
Q

Mod elevated urea; mod elevated creatinine

A
  • Pre-renal azotaemia
  • Renal azotaemia
  • Post renal azotaemia
74
Q

Marked elevated urea; marked elevated creatinine

A
  • Renal azotaemia
  • Post renal azotaemia
75
Q

Mild-mod elevated urea; normal creatinine

A
  • Mild pre-renal azotaemia
  • GI bleeding
76
Q

Normal urea; mild elevated creatinine

A
  • Uncommon - heavy muscling
77
Q

Evaluation of primary haemostasis (plug formation)

A
  • 1). Platelet count - blood smear (anti-coagulated blood)
  • 2). BMBT (buccal mucosal bleeding time) - test platelet func
  • 3). Additional - clot retraction; antiplatelet Ab; platelet adhesion; platelet aggregation testing
78
Q

Prolonged BMBT

A
  • Thrombocytopoenia
  • Type I von Willebrand’s disease
79
Q

Evaluation of secondary haemostasis (clotting cascade)

A
  • 1). Prothrombin time (PT) - extrinsic pathway
  • 2). Activated partial thromboplastin time (aPTT) - intrinsic + common pathways
  • 3). Activated clotting time (ACT) - intrinsic + common pathways - severe defects in 1y haemostasis may affect result
  • 4). Additional tests - fibrin degradation products (FDPs) - indicator of inc fibinolysis
  • D - dimers - degradation products of fibrin - more specific than FDP
80
Q

BMBT

A
  • Dog = 2 - 4 min
  • Cat = 1 - 2.5 min
81
Q

Clear transudate abdo fluid, TP < 25 g/L

A
  • Hepatic cirrhosis
  • PLE
  • PLN
  • Hepatic portal tension
82
Q

Slightly cloudy modified transudate, TP > 25 g/L/< 50g/L, RBC <50,0000 / µL

A
  • Caudal vena cava compression
  • Cardiac tamponade
  • RHS heart failure
83
Q

Sterile, straw-coloured exudate, TP > 25 g/L, RBC variable

A
  • FIP
  • Feline lymphocytic cholangitis
  • Pancreatitis
  • Neoplasia
84
Q

Non-sterile, red/dark yellow exudate, TP > 25 g/L, RBC variable

A
  • GIT perforation
  • Penetrating wound
  • Ruptured pyometra
85
Q

Hyposthenuric

A
  • < 1.008, more dilute than glomerular filtrate
  • Some renal tubular func as filtrate altered
  • Kidney can dilute glomerular filtrate, but cannot concentrate it
  • Lack of ADH - diabetes insipidus
  • Resistance to ADH - diabetes insipidus
  • Inc water consumption - 1y polydipsia
  • Lack of medullary conc ability
86
Q

Isosthenuric

A
  • 1.008 - 1.012 equivalent conc to glomerular filtrate tubular - func unknown
  • Kidney can neither dilute nor conc glomerular filtrate
87
Q

Hypersthenuric

A
  • > 1.015 - more conc than glomerular filtrate
  • At least some renal tubular func
  • Urine is normally hyperthenuric
88
Q

High USG

A
  • Diseases associated w/ PUPD
  • Hepatic insufficiency
  • Hyperadrenocorticism
  • Hyperthyroidism
89
Q

Blood gas analysis

A
  • Stored anaerobically, w/ no space adjacent to sample for gases to evaporate
  • In anticoagulant treated syringe
  • Processed within 15 min
  • Place on ice until analysis to minimise cell metabolism
90
Q

Gel tubes

A
  • Separator gels - contain particles which activate clotting -> speed up process + reduce risk of haemolysis
  • Separates cells + continued metabolism from serum/plasma
  • After centrifugation, no further manipulation required
  • Non-tube gel tubes - serum/plasma carefully removed from sediment cells + placed in clear glass/plastic tube