Hematopoiesis and RBC Maturation

Platelets

Described as 'petites plaques' by Giulio Bizzozero

Wright stain

Developed by James Homer Wright

Basophil

Referred to as 'poor relatives' of mast cells

RBC

Described as 'worms in blood'

Thrombocytes

True blood cells maintaining vessel integrity and hemostasis

Hematocrit

Ratio of packed RBC volume to whole blood volume

RDW

Expresses variation in RBC volume, the fourth RBC index

MCV

Reflects RBC diameter in blood, a RBC index

MCHC

Reflects RBC staining intensity and central pallor, a RBC index

MCH

Expresses the mass of hemoglobin, a RBC index

RBCs vs. WBCs

RBCs are 500 to 1000 times more numerous than WBCs

CBC Parameters

WBC differential provides extensive diagnostic information

Handwashing Importance

Critical after visible contamination, glove changes, and activities

Glove Change

Necessary after patient contact, contamination, or damage

Eyewear Usage

Essential for protection from aerosol mists, splashes, or sprays

Proper Labeling

1:10 bleach solution must be labeled with solution details

Fire Extinguisher Placement

Must be placed every 75 feet and checked monthly

Fire Detection Systems

Should be tested every 3 months for proper functioning

Chemical Arrangement

Chemicals should be arranged by hazard class, not alphabetically

Safety Equipment Distance

Safety showers and eye wash stations every 100 feet or within 10 seconds

Improper Disposal

Common cause of needle punctures or sharp object injuries

Lab Coat Requirements

Fluid-resistant, long-sleeved, and buttoned outer covering

Hepatitis B Virus Survival

Can survive on surfaces for at least 1 week

Indirect Transmission

Occurs when touching contaminated surfaces and then mucous membranes

Hand Washing Importance

Critical to prevent infectious disease spread, especially for phlebotomists

Biohazard Symbol Color

Red or red-orange (Rodak's), fluorescent orange (Henry's)

Eosinophil Count Variation

Lower in the morning, increase in the afternoon due to hormone levels

Exercise Impact on Blood

Increases various blood constituents, including white blood cell count

Fasting Definition

No food or beverages except water for 8 to 12 hours before blood draw

Lipemia

Increased lipids causing serum turbidity

Tourniquet

Device applied inches above venipuncture site

Venipuncture Angle

Angle of needle insertion, typically 15 degrees

Evacuated Tube System (ETS)

Common blood collection method using tubes

Needle Holder

Device for securing double-pointed needles

Needle Size

Common adult venipuncture needle: 21 gauge, 1 inch

Flash Window

Indicator in needle hub for successful venipuncture

Anticoagulant Tubes

Tubes needing gentle inversion after collection

Winged Blood Collection Set

Useful for difficult blood draws, e.g., children

Cross-Contamination

CLSI-recommended order of draw to avoid errors

Hematoma

Swelling from blood leakage around puncture site

Petechiae

Small red spots from blood escaping into skin

Syncope

Fainting response requiring immediate action

Hemoconcentration

Increased blood components due to prolonged tourniquet use

Hemolysis

Blood sample destruction from various collection errors

Venipuncture

Avoid burned, edematous, or scarred veins for blood draw

Patient Rights

Patients can refuse blood draws; nurse or physician may intervene

Skin Puncture

Preferred method for newborns; mix of fluids and blood

Povidone-iodine

Antiseptic used for skin cleansing before procedures

Specimen Transport

Carry samples upright to prevent clot disruption and hemolysis

Cold Agglutinin Titer

Refrigeration before serum removal falsely decreases this

EDTA

Common anticoagulant for hematology tests

Environmental Factors

Ambient temp, altitude, humidity, and sunlight affect samples

Quality Control

Processes to ensure assay validity, accuracy, and precision

Quality Assurance

Involves preanalytical, analytical, and postanalytical variables

Analytical Variables

Includes staff competence and laboratory procedures

Laboratory Procedure Manual

Document containing approved policies, procedures, and protocols for reporting results

Test Requisitioning

Requesting a lab test with patient details, specimen source, and analyses to be performed

Pre-Analytical Assurance

Ensuring correct test orders, legible requisitions, patient identification, and proper specimen collection

Specimen Collection

Process of identifying, preparing, and collecting patient samples for testing

Total Testing Process (TTP)

Primary focus for ensuring quality in the clinical laboratory

ISO 15189:2007

Standard for medical labs to develop quality management systems and assess competence

Diagnostic Efficacy

Evaluation using true positive, true negative, false positive, and false negative outcomes

Prevalence

Total number of events or conditions in a broadly defined population

Incidence

Number of events occurring within a randomly selected group over a defined time

Delta Check

System comparing current analyte results with the most recent previous analysis for the same patient

Coefficient of Variation (CV)

Ratio of the standard deviation to the mean, expressed as a percentage

Validation

Activity involving procedures to determine accuracy, specificity, precision, limits, and linearity

Slope

Measurement of proportional systematic error in relation to analyte values

Y-Intercept

Measurement of constant systematic error between new and reference assays

Additive tubes

Tubes for proper mixing of specimens

Specimen labeling

Correctly labeling specimen tubes for identification

Specimen transport

Delivery of intact specimens in a timely manner

Specimen temperature maintenance

Ensuring specimens are kept at the correct temperature

Specimen centrifugation

Correctly centrifuging specimens for testing

Autoverification parameters

Ensuring correct parameters for autoverification of results

Turn-around time

Recording and analyzing the time taken for tests

Patient education

Explaining specimen collection to patients for satisfaction

Decontamination

Cleaning work surfaces with bleach or disinfectant

Bleach characteristics

Broad-spectrum antimicrobial activity, non-toxic residue, fast acting

Refrigerator storage

Storing blood specimens for hematology studies for a specific time

Mitosis

Replication process in nucleated body cells except ova and sperm

Meiosis

Cell division unique to gametes producing genetic variability

Chromosome Homologue

One member of a chromosome pair inherited from a parent

Autosomes

22 pairs of chromosomes excluding sex chromosomes

Sex Chromosomes

Chromosomes determining biological sex (X and Y in humans)

PT and aPTT Sample Handling

Protocol for handling blood samples in sodium citrate tubes

Preventive Maintenance Criteria

Mandatory recalibration factors for instrument systems

Calibration

Comparing instrument measurement to a known constant

Control Specimen

Similar to patient's sample with a known value for testing

Standards

Highly purified substances for accuracy measurement

Systematic Drift

Control value progressively moving in one direction

Dispersion

Increase in random errors or lack of precision

Shift

Abrupt change indicating sudden problem development

Hematopoiesis

Regulated blood cell production process including renewal and differentiation

Myeloid to Erythroid Ratio

Normal ratio of myeloid to erythroid cells in adults (3:1)

Myeloid to erythroid ratio

Normal ratio in adults

Trabeculae

Calcified bone projections forming a honeycomb matrix

Red marrow

Active marrow with developing blood cells

Yellow marrow

Inactive marrow with adipocytes and mesenchymal cells

Retrogression

Process of replacing active marrow with adipocytes