Automated analyzers, sample collection, and sample handling (Vet 152)

Vocabulary flashcards covering automated analyzers, collection methods, anticoagulants, sample handling, and basic hematology concepts from Vet 152 notes.

Automated hematology analyzers

Cost-effective devices that perform CBCs daily, reducing labor and improving data reliability.

CBC

Complete Blood Count; a routine hematology test run by analyzers.

RBCs

erythrocytes, red blood cells

WBCs

leukocytes, white blood cells

Platelets

thrombocytes, involved in blood clotting.

Impedance analyzer

Counts cells by measuring changes in electrical conduction as cells pass between electrodes.

Quantitative Buffy Coat (QBC) system

• Uses centrifugation to separate cells by density

• Uses fluorescence to differentiate cell types

Laser flow cytometry

Analyzes cells using focused laser beams to evaluate size, density, and light scatter.

RBC indices

Hct, MCV, MCH, and MCHC used to describe red blood cells.

Hematocrit (Hct)

Percentage of blood volume occupied by RBCs; often calculated from CBC.

MCV

Mean Corpuscular Volume; average size of red blood cells.

MCH

Mean Corpuscular Hemoglobin; average hemoglobin per RBC.

MCHC

Mean Corpuscular Hemoglobin Concentration; average hemoglobin concentration in RBCs.

Electronic Cell Counters Used to determine:

RBC indices

Partial WBC counts

Platelet counts

Reticulocytes

Reticulocytes

Immature red blood cells referenced in CBC/indices.

Manual cell counts

Direct counting of cells (RBCs/WBCs) using devices like a Hemocytometer or Leukochek.

Hemocytometer

Counting chamber used to determine cells per microliter of blood.

Chemistry Analyzers

• Wet analyzers

  • Uses liquid reagents

• Dry analyzers

  • Pre-measured reagents on strips or pads

Electrolytes

Glucometer

Device used to measure blood glucose concentration.

Hemoglobin testing hemoglobinometer

Assesses hemoglobin content by lysing cells and comparing color to a standard; often with automated analyzers.

Low hemoglobin: anemia

high hemoglobin: dehydration or polycythemia

Low quality sample

hemolysis

unclean sample

not fasted

too much neg pressure

Sample quality

High-quality samples yield reliable results; avoid lipemia, icterus, hemolysis.

don’t use jugular when

collecting samples from patients with clotting disorders or anxiety.

why use vein more than artery

Veins are larger, easier to access, and typically have less pressure than arteries, making them safer and more suitable for sample collection.

75% in veins

when do we use an artery

Typically used for arterial blood gas analysis or when venous access is difficult.

Vacutainer system

Vacuum blood collection system with needle(double needle), holder, and collection tubes.

1.Needle

2.Needle

3.Vacuum tube

4.Vacuum tube

5.Holder

can fill multiple tubes with one stick

Labeling and documentation

Record date/time, patient name/ID, owner; essential for accurate results.

Order of draw

‒Vacutainers should be used and tubes collected in this order

•Citrate first BLUE

•Plain red top or white

•Tiger top – serum separator

•Green – heparin

•Lavender – EDTA

•Gray – potassium oxalate or sodium fluoride

Buffy coat

Whitish-gray layer of WBCs and platelets between plasma and RBCs after centrifugation.

Plasma

Fluid portion of blood with anticoagulant; contains proteins, electrolytes, etc.

Serum

Fluid from clotted blood; plasma without fibrinogen.

Anticoagulants

Substances that prevent clotting; chosen based on tests required.

There is NO one anticoagulant appropriate for all tests and there is NO one blood tube appropriate for all tests.

If unable to run test within 1 hour –refrigerate; do not freeze

Tubes with NO ANTICOAGULANT

• Chemistries

• Red top (plain or clot activator)

• White top (plain)

• Serum separator (SST)

  • Gel clot activator 

• Serum = plasma that has had fibrinogen removed (during the clotting process)

Tubes with ANTICOAGULANT

• Hematology (CBC-RBC/WBC)

• Purple top (EDTA)

• Green top (Lithium heparin)

• Others

• Plasma = fluid portion of whole blood that has not been allowed to clot.

EDTA

Ethylenediaminetetraacetic acid; lavender top; preserves cell morphology for hematology.

Lithium Heparin

Green top; preserves plasma for chemistry with minimal interference,

Disadvantage:  may interfere with some chemical assays

Clumps WBCs

Sodium citrate

Blue top; anticoagulant for coagulation studies; requires correct fill volume.

clotting times

Specific coagulation tests require certain blue top tubes.  For example, some are 3.2% and some are 3.8%.  Using the wrong tube will invalidate any testing. 

Most sensitive

Sodium fluoride

Glucose preservative (gray top); can interfere with some enzymatic assays.

Oxalates

Sodium/potassium/potassium oxalate anticoagulants; may inhibit certain enzymes.

Citrates

Sodium or lithium citrate; anticoagulant for coagulation tests; binds calcium.

Sample Volume

• Dependent upon quantity of serum or plasma needed

• Well-hydrated animal (PCV 50%)

  • 50% cells, 50% fluid

  • 10 mL blood = 5 mL fluid

• Dehydrated animals (PCV 70%)

  • 70% cells, 30% fluid

  • 10 mL blood = 3 mL fluid

Blood to draw (mL)= Plasma needed (mL)​ / Plasma Known as a fraction

PCV (Packed Cell Volume)

Measured hematocrit; percentage of blood that is RBCs after centrifugation.

Hematocrit vs PCV

Hematocrit is calculated; PCV is measured; values may differ if factors affect MCV.

Microhematocrit tubes

–Red ring – heparinized

–Blue ring – not treated

if already heprinized use blue

Buffy coat and plasma layers in PCV

Buffy coat is WBCs/platelets; plasma is the liquid layer above the slime; encourage accurate reading.

can see parasites in Buffy coat

–HW microfilaria

–Acanthocheilonema reconditum

Calculation for estimate of RBC count:

Divide PCV by 6

Polycythemia vera

A blood disorder characterized by an increased number of red blood cells in the bloodstream, often leading to increased blood viscosity and potential complications.

less oxygen in blood

Secondary or relative Polycythemia

is an increase in red blood cells due to a physiological response to factors such as hypoxia or dehydration, rather than a primary blood disorder.

Refractometer for TP

Measures total protein in serum/plasma; reading affected by lipemia.

need fasted

Lipemia/Icterus/Hemolysis

Interfering plasma/serum characteristics that can mislead results.

Plasma layer

–Normal – clear to pale yellow

–Cloudy – lipemic

–Reddish tinge – hemolyzed

–Deep yellow – icteric

Hemoglobin Testing

Rough estimate can be found by dividing the PCV by 3

Impedance Analyzers measure changes in electrical conduction as a solution of cells passes between two electrodes.

True

EDTA is not preferred for hematologic studies.

False

What is the correct order for collecting blood samples using Vacutainers?

Citrate, plain red top or white, tiger top, green, lavender, gray

Hematology samples should be processed immediately.

True

What is the purpose of the buffy coat layer in a blood sample?

layer contains white blood cells and platelets