Interpretation of CBC and Abnormal Cell Morphologies Flashcards
(31 cards)
Hb, MCV and MCH - interpretations
Hb (RR 11.9-15.1)
- low = anaemia (many causes)
- high = polycythaemia (uncommon) – can be primary or secondary
MCV = mean cell volume (RR 83-98) MCH = mean cell Hb (colour) (RR 28-34)
==> create DDx for anaemia based on MCV and MCH
Microcytic hypochromic anaemia
- Fe def anaemia
- thalassemia
Macrocytic anaemia
- megaloblastic anaemia due to Vit B12 or folate deficiency
- alcoholism
- liver disease
- hypothyroidism (rare)
- MDS
Normochromic normocytic anaemia
- acute blood loss
- anaemia of chronic disease
RBC, Hct, MCHC, RDW - interpretations
RBC
- increase RBC + anaemia = thalassemia trait
Hct = proportion of red cells in blood sample
- increase due to increase red cell mass e.g. polycythaemia or decreased plasma volume
MCHC = mean cell Hb concentration (not too useful)
- increase in spherocytosis (autoimmune or hereditary)
RDW = red cell distribution width
- increase if heterogenous red cell sizes e.g microcytic
Neutrophils - causes of increase/decrease
Neutrophilia
- infection (bacterial, fungal), inflammation
- malignancy
Neutropenia
- commonly after chemotherapy
- antibiotics
- viral infection
- immune causes
- a/w risk of infection when severe (ANC <0.5x10^9/L)
Lymphocytes - causes of increase/decrease
Lymphopenia
- immunosuppressive drugs
- viral/bacterial infection
- sepsis
- autoimmune disease
Lymphocytosis
- reactive
- lymphoproliferative neoplasm e.g. CLL
Monocytes, eosinophils, basophils - causes of increase, decrease (for monocytes)
Monocytosis
- chronic infections or granulomatous processes
Monocytopenia:
- hairy cell leukaemia
Eosinophilia
- secondary: parasite infection, allergy, asthma, drugs, lymphoma
- primary (rare): myeloproliferative neoplasms
Basophilia (rare)
- myeloproliferative neoplasm e.g. CML
Platelets - caution, causes of increase/decrease
RR: 150-400
Thrombocytopenia
- always consider spurious result due to platelet clumping (check morphology!!) e.g. difficult blood taking, reaction to EDTA
- drug, viral infection
- ITP, TTP
- hereditary (rare)
Thrombocytosis
- secondary: Fe def, infection, chronic inflammation, malignancy, surgical asplenia
- primary: essential thrombocythaemia (myeloproliferative neoplasm)
Purpose of analysing blood cell morphology
DDx of anaemia
DDx of thrombocytopenia
Identification and characterisation of leukaemia and lymphoma
Speedy diagnosis of certain specific infections e.g. malaria for quick Mx
Microcytic, hypochromic
Microcytosis = smaller than nucleus of lymphocyte Hypochromasia = pallor >1/3
DDx:
Fe deficiency anaemia
Thalassemia
Pencil cells
Fe deficiency anaemia
Target cells
Thalassemia
HbC and HbE disease
Liver disease
Fe deficiency
Tear drop cells
Thalassemia Marrow fibrosis (primary or secondary to infiltration)
In small amount, may also be due to Fe deficiency, megaloblastic anaemia etc –> r/o marrow fibrosis if large amounts
Macrocytic (oval macrocytes)
Megaloblastic:
Vit B12 deficiency
Folate deficiency
Non-megaloblastic:
Alcoholism, liver disease
MDS
Hypothyroid
Polychromasia (multiple colours)
Reticulocytosis - young RBC, bluish
- -> due to HA, haemorrhage
- -> indicates effective erythropoiesis
Nucleated RBC
Immature RBC normally in BM only
==> bone marrow damage/infiltration or stress
Spherocytosis
No central pallor and increased Hb content
Hereditary spherocytosis (membrane disorder) Autoimmune HA Alloimmune HA (e.g. haemolytic disease of newborn, delayed transfusion reaction)
Sickle cells
Malaria advantage
Schistocytes
Red cell fragments due to shearing forces from damaged endothelium and platelet aggregation/fibrin deposition
Microangiopathic HA
- disseminated cancer
- DIC, HUS, TTP
Leaking prosthetic heart valves
“Bite” cells/ keratocytes
G6PD deficiency
- oxidant induced haemolysis (impaired glutathione synthesis or pentose shunt)
Red cell agglutination
Cold haemagglutination disease, atypical pneumonia
Rouleaux
Hyperproteinaemias e.g. plasma cell myeloma, physiological during infection when Ig increases
Howell Jolly bodies
Smooth single round inclusion which are remnant of nuclear chromatin
Post-splenectomy, functional hyposplenism
Megaloblastic anaemia
Abnormal erythropoiesis
Basophilic stippling
Multiple bluish dots which are abnormal aggregates of ribosomes
Thalassemia
Lead poisoning
Circulating granulocytic precursors
Reactive conditions e.g. stress
Bone marrow regeneration
Neutrophils with toxic granules and cytoplasmic vacuoles
Sepsis
