Hema 1 LESSON 1 Flashcards
Hema means?
Blood
Logos means?
Discourse
Hematology encompasses the study of blood cells and coagulation
Includes:
a.analyses of the concentration, structure, and function of cells in blood;
b.their precursors in the bone marrow;
c. chemical constituents of plasma or serum intimately linked with blood cell structure and function;
d. function of platelets and proteins involved in blood coagulation.
BASIC PROCEDURES PERFORMED IN THE HEMA LAB
Peripheral smear
ESR
Coagulation test
CBC (Complete Blood Count)
WBC count
RBC Count
Differential Counting platelet count
hemoglobin/hematocrit
MCV (mean corpuscular volume)
MCH ( Mean Corpuscular hemoglobin)
MCHC (Mean Corpuscular Hemoglobin Concentration)
A thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically.
Peripheral smear
Test measures how quickly red blood cells settle to the bottom of a test tube.
ESR - Erythrocyte Sedimentation Rate
What are the coagulation tests?
PT - Prothrombin time
APTT - activated partial thromboplastin Time
D-dimer
FUNCTIONS of HEMATOLOGY LABORATORY
*Establish a diagnosis or rule out a diagnosis
*Confirm a physician’s clinical impression of a possible haematological disorder
*Detect an unsuspected disorder
*Monitor the effects of therapy
*Detect minimal residual disease following therapy
QUALITY ASSESSMENT IN THE HEMA LAB
Monitors the following
1.Test requests procedures
2.Patient Identification
3.Specimen procurement
4.Specimen labelling
5. Specimen transportation & processing procedures
6.Lab Personnel performance
7.Lab instrumentation, reagents, controls
8.Turnaround time
9. Accuracy of the final result
Components of Quality Assessment – to ensure excellence in performance.
What are the 3 distinct phases?
1.Pre analytica
2.Analytical
3.Post analytical
NON ANALYTICAL FACTORS
1.Qualified personnel
2.Laboratory policies
3.Laboratory procedure manual
4.Test requisitioning
5.Preventive maintenance of equipment
6.Appropriate methodology
What is quality control?
monitors the accuracy & precision
FUNCTIONS OF A QUALITY CONTROL PROGRAM
1.Provides a guide to the functioning equipment, reagents & individual technique.
2.Confirming the accuracy of testing when compared with reference values
3.Detecting an increase in the frequency of both high & low minimally acceptable values
4.Detecting any progressive drift of values to one side of the average value for at least 3 days
5.Demonstrating an abrupt shift or change from the established average value for 3 days in a row
QUALITY IN PHLEBOTOMY
-Appropriateness of the test request
-Patient and sample identification
-Criteria for acceptance and rejection of specimens
-Communication and interpretation of results
BLOOD COLLECTION SUPPLIES & EQUIPMENT
1.Prepare supplies and have them readily available.
2.Review the minimally acceptable volume of blood for an individual assay or group of assays.
3.Determine the minimally acceptable volume of blood for each type of collection tube.
4.Develop a plan and an alternative plan each time a phlebotomy procedure is performed.
PATIENTS WITH SPECIAL CONSIDERATIONS
-Pediatric Patients
-Adolescent Patients
-Geriatric patients
commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time.
ANTICOAGULANTS
What are the 3 types of anticoagulants using in Hema?
1.Dipotassium ethylenediaminetetraacetate
2.Sodium citrate
3.Heparin
*anticoagulant of choice for blood cell counting and sizing
- most commonly used anticoagulant
- produce less shrinkage of RBCs and less of an increase in cell volume on standing.
- prevents clotting by chelating calcium
EDTA
-removes calcium from the coagulation system by precipitating it in an unusable form.
- effective anticoagulant because of its mild calcium-chelating properties.
- 3.2% used for coagulation studies
- correct ratio is 1:9
- excess of anticoagulant can alter expected dilution of blood and produce errors in results
- anticoagulant for PT and aPTT
Sodium citrate
in vitro and in vivo anticoagulant
- it inactivates the blood clotting factor thrombin
- anticoagulates blood by inhibiting thrombin and factor Xa.
- used to coat capillary blood collection tubes.
HEPARIN
VACUTAINER METHOD
ORDER OF DRAW
1.Blood culture – blood culture bottles
2.Sodium citrate – blue top
when using a winged blood collection tube – use a discard tube – tube must be non-additive, no clot activator or coagulation tube.
- Serum tubes- with or without clot activator, with or without gel (red or yellow top)
- Sodium or Lithium heparin – green top
- EDTA – lavender, dark pink
- Gray – Sodium fluoride / Potassium oxalate
Factors that Increase the Risk of Hemolysis
*Use of needle that is too small or too large
*Jostling and jarring of tubes in transit can lyse the RBCs
*Pressing the syringe plunger to force the blood into the tube
*Drawing blood specimen from an intravenous or central line
*Under filling a tube so that the ratio of anticoagulant to blood is greater than 1:9
*Reusing tubes that have been refilled by hand with inappropriate amount of anticoagulant
*Mixing a tube vigorously
*Failing to let alcohol or disinfectant dry
*Leaving the tourniquet for more than one minute
BLOOD COLLECTION
What are the three general procedures for obtaining blood are?
1.Skin puncture (capillary)
2.Venipuncture
3.Arterial puncture
*frequently used when only small amount of blood are required.
*For hemoglobin quantitation
*For WBC and RBC count and smear preparation
*When venipuncture is impractical (infants, severe burns, extreme obesity, etc)
SKIN PUNCTURE (CAPILLARY)
Site of puncture for adult and children?
palmar surface of the tip of the ring or middle finger or free margin of the ear lobe.
Site of puncture for Infants?
plantar surface of the big toe or the heel.
Note: Edematous, congested and cyanotic sites should not be punctured. Cold sites should not be punctured as samples collected from cold sites give falsely high results of hemoglobin and cell counts. Site should be massaged until it is warm and pink.
Advantages of capillary blood
- It is obtained with ease.
- It is the preferred specimen for making peripheral blood films since no anticoagulant is added that affect cell morphology.
Disadvantages of Capillary Blood
- Only small amounts of blood can be obtained and
repeated examinations require a new specimen. - Platelet count cannot be performed on capillary
blood since some platelets are unavoidably lost by adherence onto the wound. - Precision is poorer in capillary than venous blood
because of variation in blood flow and dilution with
interstitial fluid. - Blood in microtubes frequently hemolyse and hemolysis interferes with most laboratory tests
- used for most tests that requires anticoagulation or larger quantities of blood, plasma or serum.
VENOUS BLOOD COLLECTION
Sites of Puncture
*Forearm
*wrist
*ankle
The veins in the antecubital fossa of the arm are the preferred sites for venipuncture
*Cephalic vein
*Median cephalic vein
*Median Basilic vein
Advantages of venipuncture
-Provides a sufficient sample
-It reduces the possibility of error resulting from dilution with interstitial fluid or constriction of skin vessels by cold that may occur in taking blood by skin puncture.
-Venous blood yield more dependable results as the specimen comes directly from the circulation
Disadvantages of venipuncture
- It is a bit a lengthy procedure that requires more
preparation than the capillary method. - It is technically difficult in children, obese
individuals and in patients in shock.
Vacutainer method of blood collection
It is an ideal means of collecting multiple samples with ease. The multiple sample needle used in the vacutainer method has a special adaptation that prevents blood from leaking out during exchange of tubes.
What are the phlebotomy problems?
*Refusal by the patient to have blood drawn.
*Difficulty in obtaining a specimen because the bore of the needle is against the wall of the vein.
*Movement of the vein.
Inadequate amount of blood in an evacuated tube.
*Improper anticoagulant.
*Sudden movement by the patient or phlebotomist that causes the needle to come out of the arm prematurely.
*Blood clot formation in anticoagulated tubes.
*Fainting or illness subsequent to venipuncture.
