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
2
Q
Citrate sample tube
A
- Coagulation profile
- Fibrinogen (some labs)
- PT
- APTT
- D-dimers
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
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
5
Q
Fluoride oxalate sample tube
A
- Glucose - prevents glycolysis/oxidation of glucose
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
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; phenobarbital -> immune-mediated neutropoenia
8
Q
A
- Erythrocytes
- Inc polycythaemia = phlebotomy
- Dec = anaemia
9
Q
A
- Thrombocytopoenia - < 50 units
- Low no. -> spontaneous H+
- Immune-mediated - extremely low platelet no.
- Mild dec = H+
10
Q
A
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)
12
Q
A
- Band neutrophil to metamyelocyte
- Left shift
- Smooth nucleus
- Metamyelocyte = less elongated
- Inflam response
13
Q
A
- Rabbit + exotics
- HETEROPHILS (don’t have neutrophils) - granules stain much brighter
- May observe small + large lymphocytes
14
Q
A
15
Q
A
- Precursor to macrophages
16
Q
A
17
Q
A
- Inc suggests autoimmune, myeloproliferative disorders - chronic myelogenous leukaemia (CML), primary myelofibrosis; inflammation; allergies; infection
- Value usually approx 0 anyway
18
Q
Dec RBCs
A
- Anaemia
19
Q
Inc RBCs
A
- Erythrocytosis/polycythemia
20
Q
Dec Hct/PCV
A
- Anaemia
21
Q
Inc Hct/PCV
A
- Erythrocytosis/polycythemia
22
Q
Dec MCHC
A
- Hypochromasia
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
24
Q
Dec MCV
A
- Microcytosis
25
Inc MCV
- Macrocytosis
26
Inc RDW (red cell distribution width)
- Anisocytosis
- Regenerative response
27
Blood loss
- H+
- Haemolysis
28
Mild non-regen anaemia
- PCV = 30% (dog), 20% (cat)
- Anaemia of chronic inflam disease
- Normocytic normochromic
29
Mod non-regen anaemia
- PCV < 20%
- Dec erythropoietin - CKD
30
Marked non-regen anaemia
- PCV < 15%
- Dec production of RBC
- Bone marrow disease
31
- Normocytic
- Normochromic
- Non-regenerative
- Mild
- Anaemia of chronic or inflammatory disease
32
- Macrocytic
- Hypochromic
- Often regenerative
- NB could also be in vitro storage artefact - swell + take in water
- Polychromatocytes + leptocytes (larger, folded cells)
33
- Microcytic
- Hypochromic
- Iron deficiency
- Chronic external haemorrhage
- Portosystemic shunt - alters iron met pathway
34
Serum
- 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
35
Plasma
- Clotting factors - coagulants - fibrinogen
- Plasma proteins - albumin and globulin
- Separated + run immediately from blood sample
36
What may affect biochem results?
- Haemolysis -> release of ALT + K+ from lysed RBC -> inc serum values
- Lipaemia (inc turbidity)
- Icterus (colour substances) -> inc bilirubin
37
Proteins
- Albumin, globulins etc.
- Most synthesised by liver
- Maintain oncotic pressure
- TP + albumin measurement
- Globulin = TP - albumin
38
Albumin
- 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
Globulins
- 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
Protein electrophoresis
- Differentiate types of hyperglobulinaemia
- Monoclonal - neoplasia
- Polyclonal - inflam in FIP
41
Urea + creatinine
- Azotaemia = elevation of urea + creatinine
- Pre-renal, renal, post-renal
- Assess w/ hydration status of patient + USG at time of taking serum
42
Pre-renal azotaemia
- Dehydration / hypovolaemia
- 2y to V+
- High protein meal - starve for 12 h to reduce interference
- GI H+ may result in elevations
43
Post-renal azotaemia
- Obstruction - full bladder, Hx stranguria
- Ruptured bladder - post obstruction/RTA
- Sample peritoneal fluid assess serum + fluid urea creatinine
44
Renal azotaemia
- Azotaemia (inc urea + inc creatinine) + isothenuric urine (USG: 1.008 - 1.012)
- Most concerning finding
- AKD/CKD
45
Hepatocellular damage
Inc enzymes
- ALT
- GLDH
- SDH
- (AST/LDG)
46
Cholestasis
Inc
- ALP
- GGT
47
ALT
- Alanine aminotransferase
- Hepatocellular (present in most cells)
- Transient inc = RTAs, liver or muscle damage, does not correspond w/ degree of damage
48
ALP
- 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
GGT
- Gamma-glutamyl transferase
- Specific for cholestasis + biliary tract disease, less sensitive than ALP
- Inc in neonates - colostrum intake
- Inc w/ steroids
50
Bilirubin
- Inc = pre/post/hepatic
- Pre-hepatic = haemolysis, check HCT, inc in IMHA
- Hepatic, post hepatic = cholestasis, unable to excrete
51
Bile acids
- Pre + postprandial bile acids - sample, feed, then sample 2 h post-feeding
- Func test for liver - may be affected by enterohepatic circulation disturbances
52
Ammonia
- 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
Cholesterol
- 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
Creatine kinase
- Muscle cell leakage/damage
- Marked - aortic thromboembolism in cats (thousands)
- Rapid elevation + short half-life - AST has slower response but persists for longer
55
Amylase + lipase
- 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
Calcium + phosphorus
- 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
Potassium, Sodium, Chloride
- 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
Glucose
- Ingested or synthesised by cells
- Maintained at constant level as glycogen, mostly in liver
- Insulin = uptake + glycogen synthesis
- Glucagon = glycogen breakdown
59
Hyperglycaemia
- 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
Hypoglycaemia
- 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
Urine specific gravity
- 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
Sediment examination
63
PCV
- Haematocrit tube
64
TP
- Refractometer
65
Point of care test
- Blood glucose
- Blood urea nitrogen (BUN)
- Blood lactate
66
Dec PCV; normal TP
- Haemolytic anaemia
- Aplastic anaemia
- Pure red blood cell aplasia
- Anaemia of chronic disease
- Sample haemolysed - IMHA?
67
Inc PCV; normal TP
- Polycythemia vera
- Hyperthyroidism
- Cushing's (hyperadrenocorticism)
- Haemorrhagic gastroenteritis (HGE)
- EPO-producing tumour (renal)
68
Normal PCV; dec TP
- 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
Normal PCV; inc TP
- Multiple myeloma
- FIP
- Chronic globulin stimulation - dental disease, skin disease
- Severe dehydration + anaemia e.g. CRF
- Lipaemic serum
70
Inc PCV; inc TP
- Haemoconcentration - inc RBCs, loss of plasma - dehydration
71
Dec PCV; dec TP
- Chronic blood loss (melaena)
- Blood loss - sub-acute
72
Blood lactate
- 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
Mod elevated urea; mod elevated creatinine
- Pre-renal azotaemia
- Renal azotaemia
- Post renal azotaemia
74
Marked elevated urea; marked elevated creatinine
- Renal azotaemia
- Post renal azotaemia
75
Mild-mod elevated urea; normal creatinine
- Mild pre-renal azotaemia
- GI bleeding
76
Normal urea; mild elevated creatinine
- Uncommon - heavy muscling
77
Evaluation of primary haemostasis (plug formation)
- 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
Prolonged BMBT
- Thrombocytopoenia
- Type I von Willebrand's disease
79
Evaluation of secondary haemostasis (clotting cascade)
- 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
BMBT
- Dog = 2 - 4 min
- Cat = 1 - 2.5 min
81
Clear transudate abdo fluid, TP < 25 g/L
- Hepatic cirrhosis
- PLE
- PLN
- Hepatic portal tension
82
Slightly cloudy modified transudate, TP > 25 g/L/< 50g/L, RBC <50,0000 / µL
- Caudal vena cava compression
- Cardiac tamponade
- RHS heart failure
83
Sterile, straw-coloured exudate, TP > 25 g/L, RBC variable
- FIP
- Feline lymphocytic cholangitis
- Pancreatitis
- Neoplasia
84
Non-sterile, red/dark yellow exudate, TP > 25 g/L, RBC variable
- GIT perforation
- Penetrating wound
- Ruptured pyometra
85
Hyposthenuric
- < 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
Isosthenuric
- 1.008 - 1.012 equivalent conc to glomerular filtrate tubular - func unknown
- Kidney can neither dilute nor conc glomerular filtrate
87
Hypersthenuric
- >1.015 - more conc than glomerular filtrate
- At least some renal tubular func
- Urine is normally hyperthenuric
88
High USG
- Diseases associated w/ PUPD
- Hepatic insufficiency
- Hyperadrenocorticism
- Hyperthyroidism
89
Blood gas analysis
- 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
Gel tubes
- 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
