VENIPUNCTURE & PBS Flashcards
Effects of prolonged torniquet
Hemoconcentration
Hemolysis
Slow coagulation
Condition in which venous flow is slowed
Stasis
Stasis results in the local accumulation of factor ______ and ______
Facto VIII and VWF
Distance of tourniquet
3-4 inches or 7.5 to 10 cm
Most common needle size for adult
21 gauge 1-1.5 inches
CBC is also called
Hemogram
Optimal anticoagulant concentration of EDTA
1.5 mg per ml of blood
Blood specimens for CBC must be analyzed within ____ hrs of collection (at room temp) and ___ hrs (if stored at 4C)
6 hours ; 24 hours
Blood smeares should be made within ____ hrs of collection
3 hours
Cause of excessive EDTA
Underfilled tube or short draw
Effects of excessive EDTA
Falsely low HCT
Falsely low ESR
Degenerative changes in WBCs
Falsely increase MCHC and plate count
Formation of a ring shaped molecular complex in which a metal ion is covalently bound
Chelation
A test being ordered automatically based on the results of prior tests or preset parameters
Reflex test
Any numerical value that depicts an entire population
Parameter
Tube for flow cytocentrifuge, plasma chem determination, osmotic fragility test, blood gas studies
Green top/heparin tube
Optimal heparin concentration is
15-20 u/ml of blood
Action of heparin to thrombin and factor Xa
It binds anti-thrombin (inhibits thrombin and factor Xa
A heparin formulation that cause the least interference in chemistry testing
Lithium heparin
Most widely used anticoagulant for plasma and whole blood chemistry tests
Lithium heparin
Heparin causes cellular clumping (especially of platelets) which leads to ________ (falsely elevated WBC count) and __________ (falsely decreased platelet count)
Pseudoleukocytosis ; thrombocytopenia
Critical ration between 3.2 sodium citrate and blood
1:9
Factors affecting coagulation test results (SHORTENED COAG RESULTS)
Hemolysis
Excessive agitation
Prolonged tourniquet application
Excessive needle manipulation
Platelet contamination
Factors affecting coagulation test results (PROLONGED COAG RESULTS)
Presence of clots
Increased anticoagulant concentration
Blood smears should be made within ___ hours after collection
3 hours
Disadvantages of EDTA blood smear
Plate satellitosis
EDTA induced platelet clumping
Effects of platelet satellitosis on platelets
Pseudothrombocytopenia
Effects of EDTA platelet clumping
Pseudothrombocytopenia
Pseudoleukocytosis
Correction for Pseudothrombocytopenia and leukocytosis
Recollect blood using 3.2% sodium citrate
Correction factor for Pseudothrombocytopenia and Pseudoleukocytosis
Plt count (obtained from light blue top) x 1.1
WBC ct (obtained from light blue top) x 1.1
Most frequently used blood film preparation
Two-gas’s slide method (Manual Wedge Technique)
Angle between two slide
30-45 degrees
Too high angle causes
Thicker smear
Too low angle causes
Thinner smear
Distance between the drop of blood from the label of the slide
1 cm
Size of drop of blood
2-3 mm
Too fast speed of the spreader
Too thick
Increased Hematocrit is seen in the case of
Poplycythemia vera
If hematocrit is high, the angle should be _____.
Lowered as low as 25 degrees
Decreased hematocrit is seen in
Anemia
In the case of anemia, the angle of the spreader should be ___
Raised
Buffer used for blood film staining
0.05 M sodium phosphate (pH 6.4) or
Aged distilled water (placed in a glass bottle for at least 24 hours ; pH 6.8)
pH for staining must be
6.4-6.8
Defined as any stain which contains methylene blue (and/or its products of oxidation) and a halogenated fluorescein dye (commonly eosin B or eosin Y)
Romanowsky-type stain
Basic stain, it colors the nucleus and some cytoplasmic structures ; a blue or purple color (Stained structures are described to be basophilic)
Methylene blue
An acidic stain, it colors some cytoplasmic structures ; an orange red color
Eosin
Wright stain, giemsa stain, may-grunwald stain are examples of
Romanowsky-based stain
MIDA III, HEMA-TEK, COULTER LH, SYSMEX SP10 are examples of
Automated staining
Macroscopic color of a well stained blood smear
Pink-purple
Rbc color in a well stained blood smear
Orange to salmon-pink
WBC nuclei color in a well stained blood smear
Purple to blue
Neutrophil cytoplasm color in a well stained blood smear
Pink to tan (With violet to lilac gran)
Eosinophil granules color in a well stained blood smear
Bright to orange
Problems:
RBCS gray or blue
WBCs too dark
Eosinophil granules gray
Causes: ?
Stain/buffer is too basic (most common)
Inadequate rinsing
Heparinized blood was used
Problems:
RBCs too pale or red
WBCs barely visible
Stain/buffer is too acidic (most common)
Under buffering
Over rinsing
Objective used to detect “snowplow” effect
10x objective
Objective used to locate rare abnormal WBCs
10x
Detect fibrin strands
10x
Recognize rouleaux formation or RBC agglutination
10x
Average no. Of WBCs per HPF X ______ = estimated
What is the WBC multiplication factor for HPF (40X)
2000
What is the WBC multiplication factor for OIO (50X)
3000
Storage of blood smear slide:
At least 7 days before proper disposal
Objective used for estimation and tabulation of the actual WBC differential
100X OIO
Objective used for estimation and tabulation of the actual WBC differential
100X OIO
