Laboratory Approach to Red Cell Disorders - · PDF fileLaboratory Approach to Red Cell...
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Laboratory Approach to Red Cell Disorders Ralph Green MD PhD Department of Pathology and Laboratory Medicine ISLH May 2017 Pre-Meeting Educational Workshop Honolulu
Transcript of Laboratory Approach to Red Cell Disorders - · PDF fileLaboratory Approach to Red Cell...
Laboratory Approach to Red Cell Disorders
Ralph Green MD PhD
Department of Pathology and Laboratory Medicine
ISLH May 2017
Pre-Meeting Educational WorkshopHonolulu
Anemia Classification
• Morphologic– Red cell size (micro-, macro- or normocytic)
– Hemoglobinization (hypo-, hyper- or normochromic)
– Red cell shape
• Mechanistic– Blood loss
– Increased destruction (hemolysis)
– Impaired production
Morphologic classification of anemiaa partial list…
Microcytic Normocytic Macrocytic
Iron deficiency Acute blood loss Megaloblastic anemia
Hemoglobinopathies Hemoglobinopathies Reticulocytosis
Anemia of inflammation (chronic disease)
Anemia of inflammation (chronic disease)
Liver disease
Sideroblasticanemia
Hemolytic anemia Myelodysplasia
Anemia – an algorithm
MCV-BASED ALGORITHMIC APPROACH TO ANEMIA DIAGNOSIS
RBC, Hct, Hb
Microcytic
Anemia
MCV
80-100 fl
Normocytic Macrocytic
Ferritin and iron status tests
Reticulocyte Count Blood Smear Morphology
NormalLow High
<80 fl >100 fl
Iron deficiency
anemia
Thalassemia Hemoglobin-
opathy
Anemia of chronic disease
Sideroblastic Anemia
Bone marrow ringed sideroblasts
Hemoglobin studies
NormalLow High
Aplasia Anemia of
chronic disease
Acuteblood loss
Hemolysis Chronic
blood loss
LDH BilirubinHaptoglobin
Direct anti-globulin test
No hypersegmented neutrophils
Hypersegmented neutrophils
Polychromasia Target cells
Reticulocytosis Liver disease
Liver enzymes
Vit. B12
deficiency
Folate deficiency
B12 or folate levels MMA
CRP and other cytokines
Causes of Macrocytic Anemia
Green R, Dwyre DM. Evaluation of Macrocytic Anemias. Semin Hematol. 2015 Oct;52(4):279-86
Megaloblastic Anemia
▪ Megaloblastic anemia results from an abnormality of DNA synthesis
▪ Commonest causes are deficiencies of vitamin B12 or folic acid
▪ Features include raised MCV, oval macrocytes and hypersegmented PMNs in the blood smear and nuclear/cytoplasmic dyssynchrony in the BM
Green R & Datta Mitra A Med Clin North Am. 2017 Mar;101(2):297-317
Blood Smear in Megaloblastic Anemia
Blood Smear in Megaloblastic Anemia
Bone Marrow in Megaloblastic Anemia
Laboratory Features of Megaloblastic Anemia
▪ Macrocytic anemia with raised MCV, MCH and RDW
▪ Increased SI, ferritin Tf saturation
▪ Increased LDH, indirect bilirubin
▪ Low plasma B12 or folate (and RBC folate)
▪ Raised plasma homocysteine
▪ Raised plasma methyl malonate (in B12 deficiency)
Green R & Datta Mitra A Med Clin North Am. 2017 Mar;101(2):297-317
Green R. Vitamin B12 deficiency from the perspective of a practicing hematologist Blood May 11 2017 (in press)
Vitamin B12 absorption and metabolism
Vitamin B12-Dependent Reactions
Homocysteine* + MethylTHF Methionine + THFMethyl-B12
Methylmalonyl-CoA Succinyl-CoAAdenosyl-B12
Methylmalonic Acid*
*Levels rise in B12 deficiency
Diagnosis of Vitamin B12 Deficiency
• Macrocytic megaloblastic anemia with or without neurological involvement.
• Atypical presentations (neurological syndrome without anemia or macrocytosis
• Low plasma B12 as an isolated lab finding
• Raised plasma metabolites (methylmalonic acid and homocysteine
• Low transcobalamin B12 (HoloTC) = “Active B12”
Differentiating B12 from Folate Deficiency
Condition Serum B12 Serum folate
Red Cell folate
B12 deficiency
Low
Nl or high
Low
Folate deficiency
Normal
Low
Low
Note:Plasma homocysteine is raised in B12 and folate
deficiencies. Methylmalonic acid rises in B12 deficiency
alone
Macrocytic Anemia Diagnostic Algorithm
Green R, Dwyre DM. Evaluation of Macrocytic Anemias. Semin Hematol. 2015 Oct;52(4):279-86
MCV-BASED ALGORITHMIC APPROACH TO ANEMIA DIAGNOSIS
RBC, Hct, Hb
Microcytic
Anemia
MCV
80-100 fl
Normocytic Macrocytic
Ferritin and iron status tests
Reticulocyte Count Blood Smear Morphology
NormalLow High
<80 fl >100 fl
Iron deficiency
anemia
Thalassemia Hemoglobin-
opathy
Anemia of chronic disease
Sideroblastic Anemia
Bone marrow ringed sideroblasts
Hemoglobin studies
NormalLow High
Aplasia Anemia of
chronic disease
Acuteblood loss
Hemolysis Chronic
blood loss
LDH BilirubinHaptoglobin
Direct anti-globulin test
No hypersegmented neutrophils
Hypersegmented neutrophils
Polychromasia Target cells
Reticulocytosis Liver disease
Liver enzymes
Vit. B12
deficiency
Folate deficiency
B12 or folate levels MMA
CRP and other cytokines
Differential Diagnosis of Microcytic Hypochromic Anemia
▪ Iron Deficiency Anemia (IDA)
▪ Anemia of Chronic Disease (ACD)
▪ Thalassemias
▪ Sideroblastic Anemia
Body iron fluxes
Hepcidin – “the master” regulator of iron metabolism
Anemia of inflammation (“chronic disease”)
Bunn F HemOnc Today 2013
Differentiation of IDA from ACD
Differentiation of IDA from Thalassemia minor
Discriminant Function (DF) to distinguish IDA from Thalassemia minor*
DF = MCV2 X RDW100 X Hgb
If > 65 ……….Iron DeficiencyIf < 65…………Thalassemia minor
* Green R, King R. Blood Cells. 1989;15(3):481-91
MCV-BASED ALGORITHMIC APPROACH TO ANEMIA DIAGNOSIS
RBC, Hct, Hb
Microcytic
Anemia
MCV
80-100 fl
Normocytic Macrocytic
Ferritin and iron status tests
Reticulocyte Count Blood Smear Morphology
NormalLow High
<80 fl >100 fl
Iron deficiency
anemia
Thalassemia Hemoglobin-
opathy
Anemia of chronic disease
Sideroblastic Anemia
Bone marrow ringed
sideroblasts
Hemoglobin studies
NormalLow High
Aplasia Anemia of
chronic disease
Acuteblood loss
Hemolysis Chronic
blood loss
LDH BilirubinHaptoglobin
Direct anti-globulin test
No hypersegmented neutrophils
Hypersegmented neutrophils
Polychromasia Target cells
Reticulocytosis Liver disease
Liver enzymes
Vit. B12
deficiency
Folate deficiency
B12 or folate levels MMA
CRP and other cytokines
Microcytic Anemia Diagnostic Algorithm
Blood count including red indices/smear Presumptive
diagnosis
Serum ferritin- iron- iron binding capacity- transferrin saturation
ANEMIA OF
CHRONIC DISEASEIRON DEFICIENCY
ANEMIA
THALASSEMIA
MINOR
SIDEROBLASTIC
ANEMIA
Hemoglobin studiesFor Hgb A2, F, E(hplc, genetic studies)
Definitive
diagnosis
bone marrow sideroblasts
- Infection- collagen vascular
disease- cancer
-blood/iron lossGIgynecologicalurinarypulmonaryintegumentary
- β thalassemia- α thalassemia- Hgb E disease
- congenitalX-linkedautosomalrecessive
- acquiredlead
causes
Laboratory approach to hemolytic anemia
Laboratory approach to hemolytic anemia
Anemia Classification
• Morphologic– Red cell size (micro-, macro- or normocytic)
– Hemoglobinization (hypo-, hyper- or normochromic)
– Red cell shape
• Mechanistic– Blood loss
– Increased destruction (hemolysis)
– Impaired production
Drawings of common red cell abnormalities
Don’t forget morphology! Shape and size!
Thank you! - Any questions?
Thank you! or Any questions?
