Lab investigation of FBC

Question 1

Hematocrit - define

Answer 1

Percentage of blood tube that is blood

Hct: Percentage of blood volume as RBC

Question 2

Hb test meaning

Answer 2

Concentration of Haemoglobin​,

Question 3

MCV

Answer 3

Mean corpuscular volume

Average size of RBC

Question 4

MCH

Answer 4

Mean corpuscular haemoglobin

Average haemoglobin content of RBC

Question 5

RDW

Answer 5

RDW: Range of deviation around RBC size

Question 6

Reticulocyte count

Answer 6

Reticulocyte count - precursors​

Question 7

WBC tests

Answer 7

Total WBC and differential​ Neutrophils, lymphocytes, monocytes, ​ basophils, eosinophils

Question 8

Red cells - what to expect in blood film

Answer 8

Size – big or small - anisocytosis
Colour – Hb content​
Shape: round, TDP, irregular, elliptocytes - poikilocytosis ​
Polychromasia – colour (due to residual RNA in precursors)​
Inclusions​

Question 9

White cells - what to expect in blood film

Answer 9

Numbers – too many, too few​
Normal morphology – dysplastic features
Immature cells – myelocytes, precursors,
Abnormal Cells – blasts, atypical lymphoid cells
Inclusions​

Question 10

Macrocytic megaloblastic anaemia cause + blood film

Answer 10

Results from inhibition of DNA synthesis during RBC prod

Many large immature and dysfunctional red blood cells (megaloblasts) in the bone marrow + hypersegmented neutrophils (peripheral blood)

Question 11

Acquired haemolytic anaemia blood film + cause

Answer 11

PC due to RC having residual RNA ​
No central pallor = spherocytes​

AB destroying own RBC, spleen absorbing RBC + jaundice = bilirubin released

Question 12

Sickle cell anaemia blood film

Answer 12

Target cells = distinct central pallor ​

RBC last longer than SC – BM having to compensate = polychromasia

Question 13

Tear drop poikilocytosis blood film + cause

Answer 13

Seen in myelofibrosis or bone marrow infiltration with malignant disease = due to increase in connective tissue

Cells shaped like tear drops

Question 14

Neutrophil leucocytosis ​blood film + cause

Answer 14

Too many WBC and RBC = infection/dehydration as Hb concentration goes up​

• Maloproliferative process = genetic disorder as BM makes too many WBC/RBC

Question 15

Acute myeloblastic leukaemia blood film + cause +

diagnosis

Answer 15

Abnormality in DNA that controls cell development in BM
V. high white cell count ​

20% blasts in the marrow or blood is generally required for a diagnosis of AML, normal - 5%

Question 16

Chronic granulocytic leukaemia blood film + cause

Answer 16

All stages of cell maturation represented = marked by change on philadelphia chromosome (9/22 pieces swap)

Question 17

Malarial parasitization of red cells blood film + how to confirm

Answer 17

Spread out as a “blood smear” on a microscope slide.

Specimen is stained (most often w/Giemsa stain) to give parasites distinctive appearance

Confirm with antigen test