Hematology: Blood Cells and Coagulation

Haematology

• The study of blood cells and coagulation
• Involves analyzing the concentration, structure, and function of blood cells
• Also includes studying the precursor cells in bone marrow
• The chemical constituents of plasma or serum linked to blood cell structure and function is examined
• Functions of platelets and proteins involved in coagulation are also investigated

General Characteristics of Blood

• Blood is liquid connective tissue
• Average human adults usually have around 5 liters of blood, approximately 6-8% of total body weight
• Healthy blood pH usually ranges from 7.35-7.45

Blood Composition

• Blood is approximately 55% plasma and 45% formed elements
  • Plasma consists primarily of water (91%), proteins like albumins (57%) and globulins (38%), and smaller amounts of other solutes, nutrients and waste products
  • Formed elements include platelets, leukocytes (<1%) and erythrocytes ( >99%)
• Erythrocytes:
  • Are anucleated, organelle-free, biconcave cells which facilitates gaseous exchange
• Leukocytes:
  • Are immune cells characterized as granulocytes or agranulocytes
    • Granulocytes are neutrophil, basophil, and eosinophil
    • Agranulocytes are monocytes and lymphocytes
• Platelets contribute critically in blood homeostasis:
  • Preventing excessive blood loss

Serum vs Plasma

• Serum is blood plasma with fibrinogen removed
  • Extracted after clotting has occurred
• Plasma has all coagulation proteins, including fibrinogen
  • Extracted without needing to clot the blood

General Function of Blood

• Blood transports oxygen and nutrients to cells
• Blood removes carbon dioxide and other waste from cells
• Blood regulates body temperature and pH
• Blood has a role in body defense (immunity)
• Blood contributes to coagulation
• Blood transports regulatory molecules like hormones and cytokines

Hematopoiesis

• The process of blood cell production and maturation
• The major site for many adults is red bone marrow

Introduction to laboratory Health and Safety

• Every lab worker needs to know the risks in their space and how to stay safe when handling specimens, all the way until they are appropriately wasted

Hazards

• "Biohazards": anything that can harm your health, whether it's infectious or potentially lethal
• Body fluids such as blood, urine, and spinal fluid are especially biohazardous due to their potential to contain infectious/lethal organisms
• All biospecimens should be treated as biohazardous, as infectious agents may be present long before symptoms are visible on a patient

Biohazard Exposure Routes

• Airborne: biohazards can become airborne (and easier to inhale) in the form of aerosols, splashes, and fumes
  • Airborne biohazards can occur during centrifugation, removing tube caps, and preparing specimen aliquots
• Ingestion: biohazards can be ingested is if healthcare workers neglect to sanitize hands before handling food, gum, candy, cigarettes, or drinks
  • Ingestion can also happen when workers cover their mouth with hands instead of tissue when coughing or sneezing, biting nails, chewing on pens or pencils, and licking fingers
• Non-intact Skin: biohazards can enter the body through existing damage in the skin such as abrasions, burns, cuts, scratches, sores, dermatitis, or chapped skin
• Percutaneous: passage through the skin
  • Biohazardous microorganisms can pass through intact skin as a result of accidental needlesticks and injuries from other sharps like glass or broken specimen tubes
• Permucosal: passage through mucous membranes
  • Microorganisms can enter the body through the mucous membranes of the eyes, nose, and mouth via droplets from sneezes and coughs, splashes, or aerosols

Safety Rules

• PPE (personal protective equipment) should be worn at all times to handle biospecimens
  • PPE includes lab coats, gloves, face shields, and closed shoes
• Lab coats/gowns should have long sleeves and tight-fitting cuffs, and should always be buttoned up and clean
  • Lab coats or gowns should also never be worn outside the laboratory
• Disposable gloves need to be warn during several cases
  • When there is contact with blood/bodily fluid
  • When venipuncture or finger sticks are performed
• Disposable gloves must be changed
  • After every patient
  • After visible contamination
  • When physical damage occurs
• Gloves should never be reused and should not be worn outside the lab
  • Gloves must be removed for tasks like using a telephone
• Eye and face shields should be equipped when potential for aerosols, splashes, or sprays to mucus membranes (mouth, eye, nose)
  • Such as removing caps from specimens
  • When operating a cell counter
  • When centrifuging specimens
• Handwashing: using water and soap
  • Ensure after removing gloves
  • Washing hands after handling contaminated blood
• Work surfaces must be regularly cleaned/decontaminated with a chlorine solution after completing work or spilling any infectious fluids
• Never touch , taste, or smell any chemical you do not know for a fact is harmless.
• All of the following are prohibited in laboratory:
  • Eating
  • Drinking
  • Smoking
  • Chewing gums
  • Untied long hair.

Disposables

• Contaminated lab supplies should be disposed of appropriately
  • Medical waste (yellow/red bags): any contaminated material with blood, like gloves and cotton
  • Sharps (e.g. needles, glass slides, etc.) should be disposed of in puncture-resistant containers
• Used disposable needles should not be bent, sheared, uncapped, or otherwise removed from their disposable syringes before being thrown away in a sharps container
• Broken glassware should be removed from the area via mechanical means such as brushes, dustpans, or forceps

Medical protocols

• Obtain medical attention immediately in case of accidental or inappropriate contact with biohazards
  • Any needle punctures or skin cuts should be reported to the supervisor immediately
• Hepatitis B vaccinations should be given to lab workers within 10 days of starting

Prohibitions

• Prohibit mouth-pipetting.
• Prohibit food or drink from the same refrigerator as lab specimens/reagents

General Waste

• Domestic wastes are stored in white/black color bags
  • Personal waste should be disposed in domestic garbage

The Hematology Section

• Hematology labs play a key role in healthcare, guiding diagnoses and treatment plans to improve patient outcomes

Routine Hematologic Tests

• Complete Blood Count (CBC) tests that will be done
  • Total RBC count
  • Hematocrit (hct) or Packed Cell Volume (PCV)
  • Hemoglobin
  • RBC Indices (MCV, MCH, MCHC)
  • Red Cell Distribution Width
  • Total WBC count
  • Differential Count
  • Platelet Count

CBC parts

• The red cell parameters of a CBC test include the total amount of RBCs plus hematocrit, hemoglobin, RDW, and RBC indices
• A white blood cell component includes total and differential counts

Complete Blood Count Parameters

• Platelet counts including total count and volume of platelet

Lab Specimen Procedures

• Every specimen must be received in the lab accompanied by a doctor's request

Procedures

• Most samples are venous blood collected from in/outside clinics within 12 hours
• Always transport a sealed, clear and clean plastic bag

Test Procedure

• Correctly match the patient sample and full patient information including name, date of birth and health card number
• Make sure the required test is properly labeled for performance

Special Tests in Hematology

• Reticulocyte: an immature erythrocyte and is stained by supravital stains, and contains fragments of Ribosomal Nucleic Acid (RNA)
• Peripheral blood has multiple morphologies
  • Anisocytosis for cell morphology
  • Poikilocytes for cell morphology
• G6PD (Glucose-6-phosphate dehydrogenase): part of newborn screening
  • Tests for inborn errors of metabolism
• Erythrocyte Sedimentation Rate (ESR) tests for a variety of things
  • Rate of settling of erythrocytes in an hour
  • Number of inflammatory proteins in blood sample

Laboratory functions

• They are designed to help detect and diagnose blood disorders
• Designed to assist with treatment such as blood type
• Analyze blood test with baseline data

Pre-Analytics

• Everything that occurs before the lab tests
• Indication and identification process are the core factor, then collection with transport then storage until distribution

Preanalytic process

• It's known that these errors take up 57% of the whole process of analysis from patient to results (Guder et al., 2009)
• That having been said, pre-analytics can have an error rate of consequences for as high as 25%
• The conclusion is only permitted when test results can be as good as patient samples

Common Preanalytical Errors

• Hemolysis (44%)
• Underfilling (17%)
• Underfilled (8%)

Interfering vs. Influencing Factors

• Interfering factors: alters results that disrupts methods
  • Using different testing methods helps disrupt interfering
  • Endogenous as in Internal reflection of sample to condition, and Exogenous as in the outside the sample
• Influencing change the concentration factor
  • Condition must be considered when evaluating
  • Can be classified as non-modifiable and modifiable

Phlebotomist responsibilities

• Includes organizing the blood.
• Instruct and prepare patients and label them with proper doctor ID and date
• Prepare and centrifuging the sample then saving

Patient Preparation Before Puncture

• Confirm identification of the patient
  • Name, second name date of DOB
• Use precaution with sample preparation:
  • Explain how much blood and equipment would be needed
  • Remind them the proper requirement such as fasting or allergies.

Phlebotomy

• May use a syringe or evacuated pump
• May use a monovette system too

Systems:

• Syringe (Open System):
  • Sterile, disposable
  • End of needle is inserted to the vein
  • Gauge size indicates diameter
• Evacuated tube system (vacutainer system)
  • Patient blood goes in with stopper
  • Used many times with single
  • Safer than needle and syringe
• Monovette system has safety to both

Blood collection tips

• Needle should be combined with the valve
  • Needle comes with a rubber shield
• Then inserted
  • Inserted into the holder open end.

Evacuated Collection System Method

• Specimen goes to correct blood balance
• Placed with the holder
• Is put into needle

S-Monovette System

• Combines as syringe and evacuated system.
• Vacuum is created by pulling the trigger until the click.
• Type of needles multiple helps blood collection too.

Tube colors

• Anticoagulants: Chemical substances for blood clotting
• If blood has no clotting. It will then be centrifuged and used for several test
• Make sure the test shows you follow procedures and protocols

Anticoagulant Colors

• Purple: Contain ethylamine diamine tetra acid
• Mechanism: binds with calcium in the blood. Also needed to clot blood
• EDTA maintain proper blood volume with WBCS and structure for platelets
• Blood films are used too
• Coagulation won't work in EDTA
• Blue tube: (9:1) Trisodium citrate, stops calcium
• Citrate test is always the platelet test
• Green top: 1-5mg contains arterial, eleoctrolytes, etc don't count with clumping cells
• Grey: Potassium Oxalate stops stabilzer, glucose measure

Plain Tubes

• No additive tubes
• Red or yellow cap

Equipment and materials used in Venipuncture

• Phlebotomy chart
• Winged infusion
• Needles multiple
• Order of draw from syringe

Collecting Order Factors

• From many syringe tube
• Blood, serum, etc
• CLSL order
• Blood
• Serum
• Citrate
• Heparin

Venipuncture Parts

• A vein with three parts
• Bicep
• Pronator
• Basion

Vessel Tips

• The bigger the better
• Hard to put in a needle deep vein
• Need veins in skin good and no blood.
• Deep vein ask for assist