Stagnation of venous blood flow cause by tourniquet application
Venous stasis
How does Hemoconcentration happen following tourniquet application?
When tourniquet is applied venous stasis happens (for veins to show u better). This now can lead to fluids (water and filterable components of the blood) to pass through capillary wall into tissues. This means that proteins or non filterable large molecules stay in veins causing an increase in number of these large molecules while fluid would decrease.
What increases during hemoconcentration?
- Red Blood cells
- Albumin
3.Ammonia
4.Calcium
5.Coagulation factors - Enzymes
7.Iron
8.Potassium
9.Cholesterol- increase up to 5% after 2 minutes of tourniquet application and up to 15% after 5 min.
Other factors of hemoconcentration?
- Massaging or squeezing site
- probing
- long-term IV therapy
- Draw blood from sclerosed or occluded veins
- Vigorous hand pumping - increase K to 20%, responsible for third of all elevated potassium and may increase lactate and phosphate levels
What happens when RBCs are damaged and destroyed and Hmg escapes into fluid portion
HEMOLYSIS
What would be the appearance of plasma or serum after hemolysis
Pink (slight)
Dark Pink or Light Red ( Moderate)
Dark Red (Gross)
What can cause Hemolysis inn specimen
- Drawing blood through hematoma
- Failure to wipe first blood drop in capillary puncture
3.forcing blood from syringe into tube - Frothing of blood due to improper needle size
- horizontal transfer
- mixing vigorously, shaking, inverting quickly
7.Partially filling sodium fluoride tube (gray) - pull plunger too quick
- rough handling
- squeezing site during capillary puncture
- syringe transfer delay
- using large volume tube with small diameter butterfly needle
- needle with small diameter for venipuncture
What are the physiological indications of hemolyzed specimens if collection is proper?
hemolytic anemia, liver diseases, transfusion reaction
What elevates due to hemolysis?
Ammonia, Catecholamines, Phosphates, Creatinine Kinase, Iron, magnesium, Potassium
What decreases following hemolysis?
RBC count
Partially filling tubes are called
Short draw
Short draw serum tubes such as red tops and SST are generally acceptable for testing as long as specimen is not hemolyzed and there is sufficient specimen to perform test.
TRUE
undefiled EDTA tube (excess edta) can cause?
- RBC to shrink, low blood cell counts and hematocrits, negative impact to morphological exam
- alter staining characteristics
Undefiled heparin tube (excess heparin) in plasma
- interfere with testing of come chem. analytes
Excess sodium flouride
-cause hemolysis
Undefiled coagulation tube (blue tubes)
- produce erroneous results
tubes that are same size as normal but designed to contain smaller volumes are called
short-draw tube
