CBC 1 & 2

need to finish

What are the two types of CBC analysis?

Quantitative and qualitative analysis

What three blood lineages are evaluated on a blood smear?

RBCs, WBCs and platelets

Why is a blood smear useful if an analyser is available?

It checks machine accuracy and adds morphological information

what is the purpose of a ‘clean stick’ blood collection?

To avoid activating coagulation and minimise haemolysis

Which anticoagulants are listed for CBC collection?

EDTA, heparin and citrate

How should fresh blood smears be handled after preparation?

Do no refrigerate; allow them to air dry

What does a colourful sheen on an unstained smear indicate?

A correctly made smear with a monolayer

What was the traditional method of manual quantitative cell counting?

A haemocytometer

Name five newer quantitative blood analysis technologies.

Impendance analysers, flow cytometry, QBC, VetAutoread and reference lab anlysers

What physiological signal stimulates erythropoiesis?

Decreaased oxygen (hypoxia), sensed by the kidney

What hormone increases in response to hypoxia?

Erythropoietin (EPO)

What is one effect of EPO on early RBCs?

It inhibits apoptosis

What is one effect of EPO on dividing erythroid cells?

It stimulates haemoglobin synthesis

What two methods can be used to detect erythropoisesis?

Bone marrow evaluation and reticulocyte count

What measurements make up RBC mass?

RBC count, haemoglobin, HCT and PCV

What does MCV tell you about RBCs?

Their average volume/size

What does MCHC tell you about RBCs?

Their mean haemoglobin concentration

What are the three RBC size classifications?

Microcytic, normocytic and macrocytic

What are the RBC colour classifications?

Normochromic and hypochromic; polychromatophilic cells may also be seen

What is the formula for HCT?

HCT (%) = RBC x MCV/100

How is PCV different from HCT?

PCV is measured; HCT is calculated

How close should PCV and HCT be?

They should be within 3%

What other information can be assessed with PCV?

Plasma protein and plasma appearance

What are reticulocytes?

Immature RBCs reflecting a bone marrow response to hypoxia

What does an increased reticulocyte count indicate?

A regenerative bone marrow response

What stain is used for manual reticulocyte counting?

New methylene blue (NMB)

What is the NMB concentration used in the lecture?

0.5% NMB in saline

What is the NMB mixing ratio?

3 drops of sample + 2 drops of stain

How long is the NMB mixture left at room temperature?

10 minutes

How many fields are counted for manual reticulocyte estimation?

10 fields containing approximately 100 RBCs each

How is the reticulocyte percentage reported?

As the average number of reticulocytes per 100 RBCs

What two reticulocye results should be reported?

Reticulocyte percentage and absolute reticulocyte count (ARC)

What is the ARC formula?

ARC = retic % as decimal x RBC count x 10^9/L

When should reticulocytes generally be assessed in anaemic patients?

All anaemic patients except horses

What other findings indicate reticulocyte assessment may be useful?

Increased polychromasia or nRBCs >2/100 WBCs

What special consideration applies to feline reticulocytes?

Distinguish aggregate from punctate reticulocytes

What does the lecture state about reticulocytes in horses?

Horses have no reticulocytes

A patient is anaemic, macrocytic and hypochromic. What type of anaemia is suggested?

Moderate-to-marked, moderately regenerative anaemia

A patient is moderately anaemic, normocytic and normochromic. What classification is given?

Nonregenerative/preregenerative anaemia

What two RBC patterns are assessed on the smear?

Rouleaux and agglutination

In which species can rouleaux be normal?

Horses and cats

What is rouleaux associated with?

Increased total protein

What happens to rouleaux when saline is added?

It disperses

Is agglutination ever considered normal?

No, agglutination is never normal

What condition is RBC agglutination associated with?

Immune-mediated haemolytic anaemia (MHA)

What happens to agglutination when saline is added?

It does not disperse

How can rouleaux and agglutination be differentiated?

Use a saline agglutination test

What is the saline agglutination test ratio?

1 drop sample + 10 drops warmed saline

What should be warmed for the saline agglutination test?

Both the tube and the saline