MLAB 1415: HEMATOLOGY
KERI BROPHY-MARTINEZ
Chapter 15: Hemolytic Anemias
Membrane Defects
Part Two
DISORDERS

Membrane lipid disorders



RBCs can acquire lipids when plasma lipid
increase
Results in expansion of membrane and
formation of abnormal shapes
Acanthocytosis


Spur cell anemia
Abetalipoproteinemia
DISORDERS

Paroxysmal nocturnal hemoglobinuria (PNH)
Acquired intravascular hemolytic anemia
characterized by intermittent (paroxysmal) sleepassociated (nocturnal) blood in the urine
(hemoglobinurea).
 Onset is gradual ocurring mostly in middle-aged
adults of either gender.

ETIOLOGY
 Stem
cell mutation leading to abnormal
clones of differentiated hematopoietic cells.
 These clones bind complement
 At least 9 cell surface proteins that regulate
complement are missing. As a result, the red
cell membrane is markedly sensitive to
complement.

Complement is a series of proteins circulating in
the blood which, when activated, can cause
disruption of cell membranes (RBC and
microorganisms)
CLINICAL FEATURES
 Hemoglobinurea
in first morning specimen
 Hemosidinurea
 Chronic
anemia
 Infections
 Thrombosis
 5-10% of cases will convert to acute
myelogenous leukemia; 25% will convert to
aplastic anemia.
LAB FEATURES: PNH
 Hgb:
8-10 g/dL
 Leukopenia
 Thrombocytopenia
 PB
Normocytic or macrocytic
 If IDA develops: Hypochromic, microcytic
 nRBCS

DIAGNOSTIC LABORATORY TESTS

Screening test: Sugar water test


Confirmation test: Ham’s Test (Acidified Serum Lysis
Test)


Blood is incubated in a solution of sugar water. The low ionic
strength of the solution activates complement and PNH cells
are lysed.
PNH cells incubated in acidified serum will lyse whereas
normal cells will not lyse. In order to be called positive, two
conditions must be met: 1) Hemolysis occurs with the patient’s
cells and not with normal cells, 2) hemolysis is enhanced by
acidified serum and does not occur with heat activated serum
in which complement has been destroyed.
Flow cytometry
More sensitive and specific than above tests
 Immunophenptype of RBC

THERAPY

Therapy is directed at the complications that
arise from infections, anemia and thromboses.
Anemia - iron therapy or transfusion if severe enough
 Hemolytic episodes - corticosteroid therapy to
stimulate erythropoiesis
 Thromboses - anticoagulant therapy
 Bone marrow transplant if

Aplasia exists
 Patient younger than 50

REFERENES
Harmening, D. M. (2009). Clinical Hematology
and Fundamentals of hemostasis (5th ed.).
Philadelphia, PA: F.A. Davis Company.
 McKenzie, S. B. (2010). Clinical Laboratory
Hematology (2nd ed.). Upper Saddle River, NJ:
Pearson Education, Inc.
 http://tiny.cc/d59xy
