Bird 6 Flashcards
reference interval issues in birds for lab results
- High biological and laboratory variability
- Low sample sizes of most studies
- Not RI in every avian species (may have
to extrapolate) - Should not be taken as absolute values
important considerations about avian pathology that make things difficult
- High number of species
- High biological variability
- High laboratory variability for hematology
- Lack of reference values
- Pre-analytical mistakes common
- Lack of validation of lots of analyzers and assays (or cross-validation in all bird species)
normal ref range should capture what percent healthy animals? important to remember what?
- 95% of healthy animals
- 5% of healthy birds are excluded from reference
intervals - Reference intervals may not be representative
- Overlapping of normal and abnormal
what kind of ref intervals can we use with birds that may be more reliable?
*Subject-based reference intervals
- Baseline information
- Less variable than at the population level
- Show trends over time
anticoagulant of choice for birds? when do we use citrate?
- EDTA is the anticoagulant of choice in
most species - Citrate not good for hematology, but recommended for coagulation panels
what should we not do for a syringe for birds?
- DO NOT preheparinize syringes
>will dilute sample, interfere with values
consideration about psittacine cells and blood smear
- Psittaciformes’ cells are fragile, use squash prep
- Wedge method may lyse cells
- Avoid quick stains if possible
should we use automated cell counters in birds? why?
*Automated cell counting not reliable
in birds
- All blood cells are nucleated
- Much bigger RBC
- Difference in leukocyte granulates content
(e.g. peroxidase)
what technique do we have to use for CBC in birds?
*Have to rely on manual techniques *Hemocytometer and stain
*Then apply a formula
how do we get a WBC count for a bird?
WBC estimation from the smear
- Need microscope-specific formula
- Count cells in 10 fields at x40 objective
- WBC (x109/L)=( N/10)*1.5
- Anemia correction:
WBCxPCV/45
drawbacks of manual blood cell count techniques used for birds?
- More prone to error
Many different steps
Higher effect of operators and observers - Increase analytical variability
10-15% compared to machine at <2-5% - Decrease reproducibility
Normal polychromatophilia level? what does high value mean?
*Normal polychromatophilia (1-5%)
- High polychromatophilia is a sign of
regeneration
can we use anisocytosis to estimate regenerative anemia in birds?
no
- Anisocytosis is not marked in birds
RBC lifespan in bords vs mammals
*Half-life shorter than mammals
- 1 month vs 3 months
WBC Differential Count method
*Count 100 cells at the feather edge
heterophils in birds equivalnet to what?
*Heterophils equivalent to mammalian
neutrophils (without myeloperoxidase)
are eosinophils consistent in appearance in birds?
*Eosinophils appearance vary a lot
immature heterophil is called
band heterophil
toxic heterophils - whats their appearance
rehab center, often found
-degranulated
- blue background cytoplasm, vacuolated
- different coloured granules
hemoparasties found in bird blood cells
Hemoparasites
-Haemoproteus spp.
-Plasmodium spp.
-Leucocytozoon spp.
-Microfilariae, Babesia spp., Isospora spp., Trypanosoma spp.
what bird species are heterophilic vs lymphocytic?
*Heterophilic species
- Most species
>most WBCs are heterophils
*Lymphocytic species
- Lots of passerines
- Some parrots (Amazon, Quaker parrots)
- Some owls (barred owl, long-eared owl)
>most WBCs are lymphocytes
can we measure thrombocytes in burds?
*Cannot be measured, just estimated (automated systems not made for birds)
usual number of thrombocytes on microscope slide? what do we keep in mind for estimating levels
*Typically 1-5 per HPF unless presence of clumps (average several fields
*Subjective assessment
*Clumping frequent, especially with
heparin
PCV for birds
*PCV of birds is high (45-55%)
