Clinical Heme Lecture 1

What is hematology?

The study of blood and blood-forming organs.

What areas does clinical hematology examine?

Normal and abnormal development, physiology and function, death or destruction of formed blood elements, and reactions to disease.

What are the three major components seen when whole blood is centrifuged?

Plasma, buffy coat, and packed red blood cells.

What is plasma?

The liquid component of blood that contains ions, proteins, and serves as a transport medium.

What ions are found in plasma?

Calcium, sodium, potassium, chloride, magnesium, and hydrogen.

What major proteins are found in plasma?

Albumin, immunoglobulins, complement, and coagulation proteins.

What is one major function of plasma proteins?

They contribute to transport and other functions such as immunity and coagulation.

What is a major function of plasma as a whole?

It acts as a transport medium for cell nutrients and metabolites.

What are red blood cells also called?

Erythrocytes.

What protein do red blood cells contain?

Hemoglobin.

What is the primary role of hemoglobin mentioned in the lecture?

It transports oxygen and facilitates the transport of carbon dioxide.

What are white blood cells also called?

Leukocytes.

What are the five major types of white blood cells?

Neutrophils, monocytes, eosinophils, basophils, and lymphocytes.

What is the major function of white blood cells?

They provide defense against foreign antigens, such as bacteria and viruses.

What are platelets also called?

Thrombocytes.

What is the major function of platelets?

They are necessary for hemostasis.

What is a reference interval?

The expected value for a normal, healthy individual for a particular parameter.

What factors can cause physiologic differences in normal values?

Age, sex, and geographic location.

How do newborns compare with adults for RBC concentration?

Newborns have a higher RBC concentration.

How do newborns compare with adults for hemoglobin?

Newborns have a higher hemoglobin level.

How do newborns compare with adults for WBC count?

Newborns have a higher WBC count.

After puberty, how does male RBC concentration compare with females?

Males have a higher RBC concentration.

After puberty, how does male hemoglobin compare with females?

Males have a higher hemoglobin level.

After puberty, how does male hematocrit compare with females?

Males have a higher hematocrit.

Who must establish reference intervals?

Each laboratory must establish its own reference intervals.

Can reference intervals differ between laboratories?

Yes. Reference intervals for the same methods or instruments may differ between laboratories and geographic areas.

How are reference intervals determined?

By calculating the mean value from a group of healthy individuals.

What statistical range defines the reference interval in the lecture?

The mean ± 2 standard deviations.

Approximately what percentage of normal individuals falls within the reference interval?

95%.

Approximately what percentage of normal individuals falls outside the reference interval?

About 5%.

What are the two major stages of hemostasis listed?

Primary hemostasis and secondary hemostasis.

What can blood components be used for?

Therapy for hematologic and nonhematologic disorders.

What can donated whole blood be separated into?

Packed RBCs, platelets, fresh frozen plasma (FFP), cryoprecipitate, and granulocytes.

What are the three components of laboratory testing?

Pre-examination, examination, and post-examination.

What is pre-examination?

All aspects of testing that occur prior to testing that affect outcomes.

What is another term formerly used for pre-examination?

Preanalytical.

What is examination in laboratory testing?

All aspects that affect the test procedure.

What is another term formerly used for examination?

Analytical.

What is post-examination?

All aspects after testing is completed that affect outcomes.

What is another term formerly used for post-examination?

Postanalytical.

What does a clinician do when investigating a problem?

Take a medical history, perform a physical exam, and order laboratory tests as indicated.

What are three types of laboratory tests listed for investigating a problem?

Screening tests, specific (diagnostic) tests, and repeat tests.

What is a CBC?

Complete Blood Count.

What RBC parameters are included in a CBC?

RBC count, hemoglobin, hematocrit, MCV, MCH, MCHC, RDW, and morphology.

What does RBC stand for?

Red blood cell count.

What does Hb/HGB/Hgb measure?

Hemoglobin.

What does Hct/HCT measure?

Hematocrit.

What does MCV stand for?

Mean cell volume.

What does MCH stand for?

Mean cell hemoglobin.

What does MCHC stand for?

Mean cell hemoglobin concentration.

What does RDW stand for?

RBC distribution width.

What WBC parameters are included in a CBC?

WBC count, relative WBC differential count, absolute WBC differential count, and morphology.

What does WBC stand for?

White blood cell count.

What platelet parameters are included in a CBC?

Platelet count, mean platelet volume (MPV), and morphology.

What does Plt/PLT stand for?

Platelet count.

What does MPV stand for?

Mean platelet volume.

What does a platelet count measure?

The number of platelets in the peripheral circulation.

What unit is typically used for platelet count?

Per microliter (/µL).

What are PT and PTT?

Clot-based tests used to evaluate coagulation proteins (factors).

What does PT stand for?

Prothrombin Time.

What does PTT stand for?

Partial Thromboplastin Time.

What is a hematology screening test specifically listed in the lecture?

The Complete Blood Count (CBC).

What is a hemostasis screening test specifically listed in the lecture?

Platelet count.

What is another hemostasis screening test listed?

Prothrombin Time (PT) and Partial Thromboplastin Time (PTT).