Lecture 7 Flashcards
Problems in any of these components can cause changes to RBC shape, size, HGB content or cell lifespan
- Nucleus (immature)
- Membrane
- Cytoplasm
- External forces that can alter RBCs
- Central pallor occupies
approximately 1/3 of the cell’s
diameter - wellfilled’ or Normochromic
RBC Nucleus mutations
- Genetic mutations result in abnormal protein production
- Nutritional deficiencies
can affect DNA synthesis - Early release of immature
RBCs - Abnormal cell division can
cause increased or decreased RBC counts - Can also affect the size:
‒Less divisions = larger cells
‒More divisions = smaller cells
Shape of RBC and its characteristic
Biconcave
greater surface area - crucial to RBC gas exchange function
Lipid-Bilayer
Composed of Phospholipids and Cholesterol and its characteristic
-Semi-permeable
-Elasticity & Tensile strength
-Passive transportation of gases, water & glucose
-Active transportation of ions
-Phospholipids can rapidly reseal if there is membrane damage more phospholipids content can change membrane shape
Cholesterol provides tensile strength - but more tensile strength means less elasticity with shorter lifespan
Transmembrane Proteins and its characteristic
-Transport sites, adhesion sites, and signaling receptors found in or on membrane
-vertical membrane stability - membrane integrity
-Adhesion sites – changes permit RBCs to adhere to each other and vessel wall- promoting cell fragmentation, reducing flexibility, and shorten cell lifespan
-loss of transport sites can increase viscosity
Cytoskeletal Proteins and its characteristic
-Skeleton or anchorage structure on cytoplasmic side of membrane
-Overall horizontal membrane stability-supports membrane elasticity
RBC Cytoplasm and its characteristic
- Hemoglobin abnormalities
‒ Globin chain production E.g., Thalassemias
‒ Heme production E.g, Iron deficiency
‒ Assembly of the Hgb molecule ie Enzyme or protoporphyrin
abnormalities - Enzyme mutations
‒ Energy pathway(s) affected E.g., G6PD or PK deficiency
any problem in the cytoplasm has the potential to change the HCB content and shorten the lifespan
Sickle Cell Anemia
-a mutation of the Hgb molecule which causes the Hgb to polymerize, harden and form long protein chains which
elongate within the RBC
membrane
Guidelines for Grading Abnormal Findings:
- 0 – 5 % abnormalities -normal
- 5 – 10% non specific not report
*10 – 25% abnormality moderate - > 25% abnormalities marked
Abnormal RBC ‘Arrangement
Rouleaux
- RBCs in a stacked formation. *Resemble roll of coins
- Increased plasma protein levels causes RBC to stack up and stick together
*four or more RBCs stacked in tail, monolayer, and head of the PBF
* Length of ‘stack’ exceeds the width of RBC
* Central pallor is obscured due to overlapping cells
* blue background stain‒ Excess plasma protein in the smear picks up the stain
- Caused by increased amounts of plasma proteins
‒ Changes surface membrane charge
‒ Reduces zeta potential
‒ Allows cells to become loosely
joined together - Biconcave shape allows RBCs to ‘stack’ in rows rather than ‘clump
- Report only if seen in monolayer
*Seen in ‘head’ or thick end of smear as artifact
‒Multiple Myeloma/Plasma cell Myeloma
‒Chronic Liver Disease
‒Lymphomas
‒Acute and chronic inflammatory disease
Abnormal RBC ‘Arrangement Agglutination
‒RBCs clumped together with irregular mass– haphazard grouping of cells
* RBC antibodies attach to RBC antigens and cause them to randomly agglutinate
- Seen in the tail, monolayer, and head of the PBF
- Caused by IgM antibodies called Cold agglutinins
‒ IgM binds to antigens on the RBC membrane
‒ Antibodies against Ii Blood Group System - Seen in samples at room temperature
‒ Antibody thermal range is 20° to 30° C
‒ No agglutination in patient’s blood at 37° C - IgM antibodies are large and can span the gaps (or zeta potential) between RBCs
- They form a lattice joining RBCs into irregular clumps
‒ Cold Autoimmune Hemolytic Anemia
‒ IgM associated Lymphomas
‒ Multiple Myeloma
‒ Paroxysmal Cold Hemoglobinuria (rare)
Looking for Rouleaux or Agglutination
- Look under 10x
*Confirm under 40x - Look for Background staining with Rouleaux
*Mark as Moderate-obvious with many cells or Marked - most cells
‒Report Background staining
Problems with Arrangement how youd miss it
Rouleaux
Agglutination
- Rouleaux is seen as artifact in the thick area of the
PBF – make sure that you are looking at the right end
of the smear . Look macroscopically and find the tail - If Marked Agglutination is present, WBC & PLT can be
caught up in the clumps or obscured:
‒Do not perform Estimates or Differential - ‘Unable to examine WBC or platelets due to RBC agglutination’ - We must report the abnormal Arrangement
‒Increased protein in plasma - R
‒Cold autoantibodies – A - performing counter-measures (or reflex testing)
*report both Pre- treatment and Posttreatment results
Troubleshooting
Rouleaux
- Cause - increased plasma proteins
- This indicates a specific
disorder - We must reduce the samples plasma protein content to ‘disperse’ the Rouleaux
Saline Replacement
* Replace High-protein plasma with saline
‒ Test small aliquot of WholeBlood
‒ Analyze and make a new PBF
* No excess protein = No Rouleaux
* Now Estimates, Diff & Morph
assessment can be completed
Troubleshooting
Agglutination
- Cause - cold-reacting Autoantibodies
- This indicates a specific disorder
- We must stop the antibody from reacting with RBC to prevent Agglutination
Warm or Pre-Warm Technique
* Pre-warm EDTA sample to 37C
‒ IgM reacts in cold temps
* Warm, mix well & re-analyze
* Make a ‘pre-warmed’ PBF
* IgM can’t react so Agglutination no longer seen
* Now Estimates, Diff & Morph assessment can be completed
