The Practical Lab

Question 1

Which blood tubes contain anti-coagulant and which do not?

Answer 1

Serum - clotted
Heparin, EDTA, citrate, oxalate - anti-coagulant

Question 2

What do we see on biochemistry if there has been EDTA contamination?

Answer 2

Artificial hypocalcaemia and hyperkalaemia

Question 3

Which liver parameters are markers of hepatocellular damage?

Answer 3

ALT, AST, GLDH, SDH

Question 4

Which liver parameters are markers of cholestasis?

Answer 4

Cholestasis = bile not moving as it should, not moving into intestines (bile duct closed)
ALP, GGT

Question 5

Which liver parameters are markers of function?

Answer 5

Substances produced in liver - cholesterol, urea, glucose, albumin, some globulins, coagulation factors
Substances conjugated and excreted by liver - bile acids, bilirubin

Question 6

What can cause primary hepatocellular disease?

Answer 6

Trauma
Toxins
Drugs
Inflammation/infection
Neoplasia
Intrahepatic cholestasis
Bile toxicity

Question 7

What biochemistry changes reflect decreased hepatic function?

Answer 7

Increased levels of things supposed to be excreted by liver: bilirubin, bile acids
Decreased levels of things made by liver: albumin, cholesterol, urea, glucose, clotting factors

Question 8

What does a stress leukogram look like?

Answer 8

Neutrophilia
Monocytosis
Lymphopaenia
Eosinopaenia

Question 9

What characteristics of lesions are useful for clinical history?

Answer 9

Localisation
Firm/soft
Dimensions
Painful/non-painful
Ulcerated/non-ulcerated
Cutaneous/subcutaneous
Adherent/non-adherent
Aspirate appearance

Question 10

What are the two methods of fine needle aspiration (FNA)?

Answer 10

Non-suction
Suction (when non-suction technique is unsuccessful)

Question 11

Describe non-suction FNA.

Answer 11

Soft cutaneous/subcutaneous masses
Lymph nodes
Vascular lesions/organs
Needle inserted into mass, syringe removed and filled with air, syringe attached to needle

Question 12

Describe suction FNA.

Answer 12

Hard cutaneous/subcutaneous masses
Bone lesions
Needle and syringe inserted into mass, plunger pulled back, vacuum created in syringe, release plunger before removing needle from mass

Question 13

What other collection methods are there for cytology samples?

Answer 13

Impression smear
Skin scrapes
Biopsy - imprint
Ear swab - imprint

Question 14

Describe Malassezia on ear swabs.

Answer 14

Fungus - yeast
Peanut-shaped
Present in low numbers on normal skin

Question 15

Describe Diff-Quik staining.

Answer 15

Solution A (fixation) - methanol
Solution B (eosinophilic (base) staining - eosin
Solution C (basophilic (acid) staining) - methylene blue

Question 16

What should we look for on low magnification (10x) of cytology?

Answer 16

Cellularity
Preservation
Staining
Haemodilution
Cell distribution
Background

Question 17

What should we look for on high magnification (40x) of cytology?

Answer 17

Cellular vs non-cellular elements
Inflammatory vs neoplastic
Malignant vs benign

Question 18

What should we look for on high magnification (100x) of cytology?

Answer 18

Presence of cytoplasmic granules
Nuclear detail
Presence of pathogens - bacteria, fungi, protozoa

Question 19

Describe neutrophils.

Answer 19

Crisp nuclear outlines with dark purple chromatin
Cytoplasm pale, clear to slightly eosinophilic (pink)

Question 20

Describe degenerate neutrophils.

Answer 20

Neutrophils affected by toxic change
Loss of segmentation
Lighter coloured ‘fluffy’ nuclear chromatin and swollen appearance

Question 21

What are the advantages of in-house labs?

Answer 21

Fast turn-around time
Potential for improved monitoring
Smaller volume of sample needed
Available OOH/in remote areas
May save costs

Question 22

Define inter-individual factors that affect results.

Answer 22

Inherent difference between groups of animals due to effects of species, breed, age and/or sex

Question 23

Define intra-individual factors that affect results.

Answer 23

Transient differences in the same animal
Eg. diet, stress/excitement, reproductive status, drugs, method/site of blood sampling

Question 24

What pre-analytical factors can affect results?

Answer 24

Poor blood sampling technique
Haemolysed, lipaemic, icteric plasma
Wrong anticoagulant to blood ratio
Sterile vs non-sterile container
Transportation
Storage

Question 25

What analytical factors can affect results?

Answer 25

Equipment e.g. function/maintenance
Technician e.g. training
Analytical procedure e.g. technique, calibrations
Laboratory e.g. temperature, humidity

Question 26

How do we carry out quality control?

Answer 26

Control material of known composition is measured to check accuracy of analytical process
Performed during analysis to ensure validity of result
Controls are not calibrators

Question 27

What should we do if a control fails?

Answer 27

Check for reagent depletion/expiry, mechanical faults, clots
Use another aliquot of control material
Repeat control
Use new reagent, recalibrate equipment
Run routine maintenance
Consult manufacturer

Question 28

What post-analytical factors can affect results?

Answer 28

Transfer of results to patient record
Archiving results
Storing specimens