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Heme Lab

QuestionAnswer
Accuracy - Correctness of a result, freedom from error, or how close to the true value, multiple measurments - the average
Precision - (reproducibility)- measure of the closeness of the results obtained when analysis on the same sample is repeated, agreement between replicate measurments - consistancy, fewer measurments - more important than Accuracy
Reliability - Ability of a laboratory assay to produce consistent results when testing is repeated successively.
Instrumentation in Hematology does what? saves times, and increases; precision, reliability and accuracy
Some principles used on hematolgy analyzers Impedance and optical light scattering
Impedance - instruments also useful in determination of cell lines that may overlap and "look" alike Increased resistance occurs when a blood cell with poor conductivity passed through an electrical field. Each cell counts as one pulse and the amplitude of each pulse is the volume of each cell. Dilution chambers are set up and measurments are taken.
optical light scattering - allows counts on specimens with low white counts and differentials on these specimens. Single blood cells pass through a beam of light creating forward (measures cell size) and side scatter (cell complexity or granularity). Diluents are usedto make some cells "clearer" for the instrument, depending on cells to count
Most hematology analyzers use ____________ methods to determine all the counts that they do. multiple
__________ systems are used to help define what is normal and what is abnormal Flag
__________ studies are done with hundreds of specimens before new instruments go into use at each facility Correlation
On a cytogram for cellular scatter x and y axis - (up and down) Forward scatter (size) smaller to larger - (Bottom) Side scatter granularity - less to more
Variation in size of RBC Anisocytosis
Normal sized RBC MCV of 80-100 Normocytic
Large RBC >100 MCV - Macrocytic
Small RBC <80 MCV - Microcytic
Normal color RBC Normochromic
Less color RBC Hypochromic - bigger pallor
More color RBC Polychromasia - color variation
RBC shape variation Poikilocytosis
Oval shaped ovalocyte
Longer cells Elliptocyte
Longer with pointy ends Sickle cell
Tear drop Dacrocyte
fragment of a cell schistocyte
Helmet cell keratocyte
shorter spikes, not as pointy, evenly spaced echinocyte, crenated, Burr cell
longer, not evenly spaced, pointy Acanthocyte
no central pallor spherocyte
central pallor looks like a mouth stomatocyte
raised center target cell
RBC hooking together w/antibodies Agglutination
does not involve agglutination - add saline to undo in smear, sticky cells, stacked like coins rouleaux
size calculations for RBC indices
On a normal platelet curve – identify x and y axis and know what one should look like - #of platelets few to many, bottom size of platelets small to large – should look like a bell curve.
Platelet clumping will result in what for the electronic platelet count? Under counting – will count 1 large platelet instead of # of reg platelets
What stain is used for a CBC? Wright
What stain is used for a reticulocyte count? New methalane blue
What is the difference between wright and new meth blue? Supravitity (there is something else too this, like ribosones or something)
Universal precautions apply to what fluids in the laboratory? – ALL
What are howell jolly bodies made of? Nuclear fragments
List a condition in which you would see howell jolly bodies – Megaloblastic anemia
If a patient has an MCV of 70, due to lead poisoning, what term would we use to describe the condition? Microcytic chromic anemia (I don’t know about this one??)
If we are using the 40x objective, what is the total magnification? 400
What does MCHC mean and what is the formula? Mean corpuscular hemoglobin concentration –Hgb*100/Hct
A patient’s reticulocyte count is 1.0%, what could be a cause – Normal count
List the 10 parts of a CBC – RBC count, WBC count, platelet count, Hgb, Hct, MCV, MCH, MCHC, MPV, RDW
What color tube is used for a CBC? Lavendar
What anticoagulant is used? EDTA
Characteristics of a good slide – feathered end, 2/3rds of the slide, labled
Explain how to carry a microscope – One hand under the arm, one hand under the base, CAREFULLY
What are the three cellular elements that can be seen in a peripheral smear? RBC, WBC, platelets
Meaning and formula for MCV – Mean Corpuscular Volume – Hct*10/RBC
Meaning and formula for MCH – Mean Corpuscular Hemoglobin – Hgb*10/RBC
Howell-Jolly Bodies Nuclear fragments - Wright's stain or New Methylene Blue - Post splenectomy Megaloblastic anemia
Basophilic stippling ribosomes - Wright's stain or New Methylene Blue - Lead poisoning, arsenic poisoning, Thalassemia, Siderblastic anemia
Heinz Bodies denatured hemoglobin - Supravital or New Methylene Blue - G6PD deficiency, post splenectomy, unstable hemoglobin disorders
Malaria parasite Plasmodium Malaria
Cabot rings microtubules of mitotic spindle Wright's stain or New Methylene Blue Severe anemias, dyserythropoiesis
Sideroblasts Contains nucleus … Iron granules Perl's Prussian blue iron
Nucleated RBC – used to state the presence of normoblasts in the peripheral blood-includes allnormoblasts in the periph blood regardless of the stage of maturation. Typically, the circulating nucleated RBC is at the orthochromatophilic stage of differentiation
RBC Corrections – Nucleated RBCs (WBC must be adjusted when # of NRBCs exceed 5)**
Corrected WBC count = WBC*100/100+#NRBCs
With instrumentation, some instruments calculate the corrected white count for you. If upon doing the differential, you notice a significant difference in the NRBC you count vs the NRBC the machine counted, you must - uncorrect the WBC count, then recorrect it with the new number of NRBC.
Remember NRBC are always counted when observed and always reported, however, you would only correct the WBC count if the number of NRBC is greater than 5.
ESR Erythrocyte Sedimentation Rate – in general a non-specific measure of inflammatory activity
ESR Dependant on – protein composition of plasma, size and shape of erythrocytes, erythrocyte concentration
ESR up – plasma protein up, Macrocytes up, Rbc down
ESR down – Microcytes up, RBC up
Other causes of increase in ESR – female-smoker-cold-acute/chronic infections-acute coronary syndrome-multiple myeloma-osteomyelitis-PID-polymyalgia rheumatic-pregnancy-pulmonary TB-rheumatic fever-systemic lupus erythrmatosis-subacute bacterial endocarditis,waldenstrom’s macroglobinemia
Types of ESR – no longer used generally Wintrobe:blood is drawn w/EDTA tube,placed in win. tube by drawing blood up into a pipette and placing pipette in the bottom of the tube and slowly filling tube up. Potential error with air bubbles or incorrect filling of tube. Read after 1 hour in mm.
Types of ESR – Westergren:EDTA blood dilutes with .85% NaCl into calibrated west. pipette, settle 1 hour,read distance in mm between plasma and the top of the sedimented RBC column.Automated-reads in 15-30 min – converts to mm/hr
ESR Normals – adult male and children – 0-1 mm/hr, Adult female 0-22 mm/hr
What is the term used to describe variation in size of erythrocytes – anisocytosis
What is the term used to describe variation in shape of erythrocytes – poikilocytosis
An MCV of 70 indicates what about the patient’s RBC – Microcytic
What stem cell does a RBC derive from – Myeloid stem cell
MCV- formula (hematocrit x 10) divided by the RBC
MCH formula (hemoglobin x 10) divided by the RBC
MCHC- formula (hemoglobin x 100) divided by hematocrit
Nucleated RBC- count nucleated red cells during your 100 cell differential, they are reported (not as part of the differential) no matter what the count is.
White blood cell count is corrected as follows: (100 x instrument white blood cell count) divided by (100 + nucleated red blood cells counted)only IF number of nrbc counted exceeds 5. Absolutes in your white blood cell counts = total number of WBC x percent of that particular cell in the differential
Interpreting Instrument Printouts – WBC and cytogram for cellular scatter – x axis represents the side scatter, less to more granular
CLSO – Clinical Laboratory and Standards Institute – sets performance goals for internal quality and set guidelines for instrument calibration and assessment of performance criteria
Goals of instrumentation – Identify patients who have the disease & Identify patients that don’t have the disease
QC – Quality Control – Establishes performance goals, provides a high level of assurance that the instrument is working
Calibration defines -
whole blood calibrators – require the use of reference methods, materials and procedures to determine the true values –
Now, whole blood calibrators are being replaced by the use of commercial calibrators that have been assayed against reference materials – Stabilized and preserved cells suspensions can cause calibration bias
Improvements of instrumentation include: greater sensitivity, greater specificity, walk away capability – BUT tech need to be aware they must understand instrument limitations and recognize factors that interfere and cause erroneous lab results
Instrument Limitations and Interferences – These may be related to methodology or to inherent problems in the blood sample, generally defined in instrument manuals
Variation in RBC size is expressed by the RDW
List the maturation series for a RBC – Myeloid stem cell, Pronormoblast, basilphilic normoblast, polychromatic normoblast, orthochromatic normoblast, retic, RBC
Lymphocyte maturation series – Lymphoid stem cell, lymphoblast, lymphocyte
Monocyte maturation series – myeloid stem cell, monoblast, promonocyte, monocyte
Neutrophil maturation series – Myeloid stem cell, myeloblast, Neutrophilic promyelocyte, Neutrophilic myelocyte, Neutrophilic metamyelocyte, Neutrophilic band, seg.
Maturation series for platelets – myeloid stem cell, megakaryocyte, platelet
If the zone of central pallor in an erythrocyte is greater than one third of the diameter of the cell, it should be classified as what? Hypochromic
Created by: BOMLT