Laboratory Flashcards
Hazards in the lab?
Hazards in the lab?
.Clinical material
.Biological agents
.Chemicals (toxic or corrosive)
.Sharp objects
.Toxic fumes
.Eye contaminants
.Zonnoses
.Fire
Lab waste?
Lab waste?
.Infectious waste
.Contaminated sharps
.Chemical waste
.Domestic waste
Glass ware?
Glass ware?
.Wash before use
.Contaminated glass ware should be soaked in an approved disinfectant for 24 hours prior to cleaning
Microscope?
Microscope?
.Blood and bacterial smears should be examined under X10, X40 then X100 with oil in immersion.
.Urine sediments and faeces should be examined under X10 then X40.
.Parasite slides examined with the naked eye. If microscope use X5 then X10. For microscopic parasites use X10 then X40.
Centrifuge is for?
Centrifuge is for?
.Separation of blood cells from plasma or serum.
.Urine sedimentation
.Faecal analysis
Centrifuge process?
Centrifuge process?
.Sample is subjected to centrifugal force, which results in the heavier constituents of the suspension setting to the bottom of the tube while the lighter ones settle on the top.
.This is faster than leaving it to settle on its own.
.Microhaematocrit centrifuge - PCV.
Electronic analysers?
Electronic analysers?
.Biochemistry analysers
Haematology analysers
.Electrolyte analysers
.Blood gas analyers
.Hormone analyers
Commercial test kits?
Commercial test kits?
.Most utilise the enzyme linked immunosorbent assay (Elisa) test.
.The test detects the presence of specific antigens dependent on the test being undertaken.
.The test is well impregnated with appropriate antibodies for the test to be performed; the antibodies bind any viral antigens present in the sample and a dye is activated, producing a colour change that shows a positive result.
Commercial test kit list?
Commercial test kit list?
.FeLV ELISA test .FIV ELISA test .Parvovirus ELISA test .Premate test (ovulation) .Allercept e-screen test (detects immunoglobulin E in blood). .Total T4 (thyroxine 4 in cats) .Pancreatic lipase test .Heartworm .Lyme .Giardia
Autolysis?
Autolysis?
.Digestion of tissue by it’s own enzymes.
Lab samples?
Lab samples?
.Send samples by first class post, data post or courier.
Collection of blood?
Collection of blood?
.Should have the largest gauge with the shortest length to allow the sample to be taken quickly and reduce damage to RBCs.
.Venepuncture - largest accessible vein should be used.
Venepuncture sites?
Venepuncture sites?
.Dog & cat - jugular, cephalic (large dog), lateral saphenous (dogs), medial saphenous (cats).
.Rabbit - jugular, lateral marginal ear vein, lateral saphenous.
.Guinea pig - jugular, lateral marginal ear vein.
Blood sampling in birds?
Blood sampling in birds?
.Anaesthetise most birds prior to blood sampling.
Anaesthetic gel?
Anaesthetic gel?
.Apply to marginal ear vein, so less stressful.
Before putting blood into tube?
Before putting blood sample into tube?
.Remove the needle to reduce damage to the RBCs.
Anticoagulant bottle?
Anticoagulant bottle?
.Fill with blood to the ‘fill line’ so the anticoagulant is diluted correctly. Then roll to mix.
.Sample does not clot, so the study of the physical characteristics and number of cells per unit volume in the blood can be seen.
.Anticoagulants - those that block calcium and those that interfere with the enzyme systems.
.Put time on tube.
Haemolysis?
Haemolysis?
.The process of rupture of the RBCs. The plasma or serum will be pink.
Tube types?
Tube types?
.White, colourless cap - no anticoagulant
.Brown cap - serum gel tubes
.All other caps - anticoagulant in them
Plasma/ serum colour?
Plasma/ serum colour?
.Pink - haemolysis
.Milky - lipaemia
.Yellow - presence of bilirubin (liver damage)
Plasma & Serum?
Plasma & Serum?
.Plasma - contains fibrinogen that clots blood. Once blood is clotted plasma turns into serum and fibrinogen is gone.
.Serum - is plasma the fluid in which the cellular components of blood are suspended, minus the clotting factors such as fibrinogen.
.Plasma & serum are almost colourless to pale yellow.
Blood smears?
Blood smears?
.Make two smears incase one is no good.
Staining blood smears?
Staining blood smears?
.Detect changes of cells
.WBC count
.See parasites
.Number of platelets
Leucocytosis?
Leucocytosis?
.An increase in the number of WBCs above the normal range.
Leaucopenia?
Leaucopenia?
.A reduction in the number of WBCs below the normal range.
Packed cell volume and haematocrit?
Packed cell volume and haematocrit?
.PCV - is the RBC to fluid ratio in the blood. It’s expressed as a percentage or litre per litre.
.Haematocrit (Hct) - not quite the same as a PCV. As it is calculated by an automated analyser and not directly measured but describe the same thing. It is determined by multiplying the RBC count by the mean cell volume.
.Haematocrit is more accurate.
Normal PCV ranges?
Normal PCV ranges?
.Dog - 37% - 55% or 0.37 - 0.55L/L
.Cat - 24% - 45% or 0.24 - 0.45L/L
.Read PCV with TP.
Low PCV?
Low PCV?
.Anaemia
.Sedation
.Anaesthesia
High PCV & TP?
High PCV?
.Dehydration
Low PCV & TP?
Low PCV & TP?
.Aggressive fluid therapy
.Haemorrhage
Low PCV & normal TP?
Low PCV & normal TP?
.Possible increased destruction of RBCs.
High PCV & low TP?
High PCV & low TP?
.Dehydration with protein loss, e.g. haemorrhagic enteritis.
Microhaematocrit tubes?
Microhaematocrit tubes?
.Are heparinised if fresh blood is used to prevent clotting.
.Plain tubes - are used with anticoagulanted sample.
Microhaematocrit tube reading?
Microhaematocrit tube reading?
.Three quarter fill the tube, unfilled end is sealed with cristaseal, wipe clean
.Put sealed end outwards into the centrifuge and spin for approx 5 mins at 10,000 rpm with two tube diametrically opposite.
.Once spun the RBCs will be at the bottom above the sealant and WBCs & platelets on top of that with plasma on top of them.
.It is then read on the microhaematocrit reader.
Microhaematocrit reader?
Microhaematocrit reader?
.The PCV is calculated by dividing the length of the column of RBCs by the combined length of the RBC, buffy coat and plasma then multiplying by 100 to give the result as a percentage.
.(PCV% a ÷ b x 100 =) Divid the RBCs by the whole of the blood then X100 to get %.
Haemoglobin (Hb) estimation?
Haemoglobin (Hb) estimation?
.Hb levels - decreased in cases of anaemia.
.Corpuscular values - measurements of RBCs e.g. PCV and haemoglobin contents.
.Mean corpuscular volume (MCV) - indicates the average size of the RBCs.
.MCV (Fl) = PCV (1/1) x 100 12
Total red cells (10/1)
.Fl = femtolitre
Urine?
Urine?
.Examination of sample should be performed as soon as possible within 1 hour or the pH will change which will change the results.
.Colour - the pigment urochrome is responsible for the colour of normal urine.
.Rabbit urine - changes colour from yellow, orange, red and is turbid (cloudy) because of calcium carbonate.
Urine pH?
Urine pH?
.Can be found by pH papers, multireagent dip sticks or electrode pH meters.
Specific gravity (density of fluids)?
Specific gravity (density of fluids)?
.The density of a known volume of a fluid.
.Refractometer - measure specific gravity of urine. It assesses the refractive index of fluids.
.The higher the refractive index the higher the concentration of urine e.g. the specific gravity
.Before calibrate it with distilled water to see if working. The specific gravity should be 1.000 with distilled water.
Test strips?
Test strips?
.Can test for pH, protein, glucose, ketone bodies, urobilinogen, bilirubin, haemoglobin and blood in urine.
Pyuria?
Pyuria?
.Large amounts of WBCs (neutrophils) in the urine sample.
Stones (calculi)?
Stones (calculi)?
.Cystic calculi are in the bladder and uroliths are in the urethra.
Casts?
Casts?
.These are precipitated protein and form in the kidneys.
Skin scrapes?
Skin scrapes?
.Look for mites, malassezia fungi.
Tape impressions?
Tape impressions?
.Malassezia fungi
Hair plucks?
Hair plucks?
.Demodex spp, lice, ringworm and cheyletiella
Swabs?
Swabs?
.Demodex, ear wax for otodectes or malassezia.
Hair brushing?
Hair brushing?
.Ectoparasites
Skin disease signs?
Skin disease signs?
.Alopecia, crusting and scaling of skin.
.Wood lamps - allow to warm up for 5-10 mins.
Total protein?
Total protein?
.Test a rough measure of all the protein in the plasma of blood.
Glucometer?
Glucometer?
.Measures blood glucose levels.
.Feed & give injections the same time everyday & exercise the same time everyday for the same amount of time to avoid glucose upset.
Blood urea nitrogen (BUN)?
Blood urea nitrogen (BUN)?
.Measures the amount of nitrogen in your blood that comes from the waste product urea.
Serum glucose test?
Serum glucose test?
.Used to estimate blood sugar levels.