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Heme Lab
| Question | Answer |
|---|---|
| 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
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