12930639
Description
Flashcards by Alinta Kalns, updated more than 1 year ago
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Created by Alinta Kalns
about 6 years ago
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| Question | Answer |
| What haematological analysers are available in vet medicine | 1. Quantitative buffy coat systems 2. Impedance analysers 3. Laser-based flow cytometers |
| What does a quantitative buffy coat system do? | Dyes contents of buffy coat with acridine orange dye Performs cell counts based on density variation |
| What does an impedance analyser do? | Counts cells as they disrupt an electrical current |
| What do laser-based flow cytometers do? | Combine impedence, flow cytometry, and special stains to sort and count cells Measures sideline scatter (cell volume) and forward scatter (absorbance) |
| Which haematological parameters are measured? | [RBC], HGB, MCV, absolute reticulocyte count |
| What haematological parameters are calculated? | HCT, MCHC, RDW |
| How is the Haematocrit (HCT) calculated? | HCT = MCV x [RBC]/1000 |
| How is the MCHC calculated? | MCHC = [HGB]/HCT |
| How is RDW calculated? | RDW = [SD of MCV/MCV] x 100 |
| What are the 3 rules of haematology? | 1. Always group RBC, HGB, and HCT 2. HCT is roughly = 3x HGB/1000 3. An increase in MCHC shows analytical error |
| Explain how to check if HCT = 3 x HGB/1000 rule is broken | Manual PCV (PCV/100 = HCT) If PCV not = to HCT; MCV or RBC measurement error If PCV = HCT; HGB measurement error |
| Explain how to check rule 3 - MCHC increase | PCV + blood smear - Increased free HGB can increase MCHC (haemolysis, lipaemia) - Heinz bodies, spherocytes, and eccentrocytes can increase MCHC Look at HGB and HCT if not 320-360 g/L |
| What steps would you take to investigate anaemia? | 1. Look at RBC, HGB, and HCT along with TPP 2. Look at MCV and MCHC 3. Look at absolute reticulocyte count |
| Discuss relative and absolute values for WBC types | Absolute value calculates quantity of each WBC type in relation to total WBC count Relative just estimates percentage of each WBC type represented in blood |
| How do you calculate absolute values? | [WBC type]% x total WBC E.g. 70% neutrophils and 12 x 10^9/L total WBC = 0.7 x 12 = 8.4 x 10^9/L |
| Briefly discuss species variation in leukocyte differentiation | Horses, dogs, cats --> neutrophil dominant Cows = lymphocyte dominant |
| Briefly discuss degree of WBC response per species | Dog - strongest, marked 50-100 Cat - marked 50-75 Horse - marked 30+ Cow - marked 25+ |
| What is the corrected WBC count and how is it done? | Removal of nucleated RBCs from automated total WBC cWBC = machine TNCC x [100/(nRBC+100)] E.g. 25 nRBC/100 WBC counted and TNCC = 20 x10^9/L 20 x [100/25 + 100] =16 x10^9/L |
| What could cause a thrombocytosis? | Splenic contraction Iron deficiency Inflammation or neoplasia |
| What could cause a thrombocytopaenia? | Immune haemolytic thrombocytopaenia Haemorrhage If <30-50 x 10^9/L spontaneous haemorrhage may occur |
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