Medical Analysis Course Lecture 1

Questions and Answers

What effect does collecting a fluoride tube before an EDTA tube have?

It stabilizes glucose levels in the sample.

It increases calcium levels in the sample.

It reduces the need for hemolysis testing.

It can distort red blood cell morphology. (correct)

Which of the following factors is NOT a cause of hemolysis during blood sampling?

Forceful injection into the vacutainer.

Transporting the sample without any temperature control.

Collecting from a ruptured vein.

Allowing the blood to clot before centrifugation. (correct)

What is the primary role of EDTA in a blood sample?

To promote hemolysis for analysis.

To enhance the viscosity of the plasma.

To act as a buffer for pH stabilization.

To chelate calcium and prevent coagulation. (correct)

During hematopoiesis, what do hemocytoblasts develop into?

All types of formed blood elements. Signup and view all the answers

What is the pH range of plasma considered to be normal?

7.35 - 7.45 Signup and view all the answers

What is the viscosity of whole blood compared to plasma?

2.4 times that of plasma. Signup and view all the answers

Which statement best describes the function of blood in maintaining body temperature?

Blood acts as a heat sink, absorbing excess heat. Signup and view all the answers

What is a common characteristic of icteric serum?

It presents a yellowish discoloration due to high bilirubin levels. Signup and view all the answers

What blood component is primarily responsible for defense functions in the body?

White blood cells. Signup and view all the answers

What is a consequence of vigorously shaking a blood sample during transportation?

Increased likelihood of hemolysis. Signup and view all the answers

Study Notes

Introduction to Medical Analysis

Medical analysis specialists play a critical role in healthcare.
The workflow involves the journey from test requisition to results being returned to the physician.

Laboratory Errors

Errors can occur at any stage of the laboratory workflow.
Attention to detail in each phase can minimize errors.

Laboratory Workflow Stages

Pre-analytical Phase:
- Involves test ordering, patient data recording, specimen collection, and transport.
Analytical Phase:
- Focuses on specimen processing, reagent preparation, and performing tests.
Post-analytical Phase:
- Includes interpreting and reporting results accurately.

Pre-Analytical Phase

Essential practices:
- Accurately read request forms and deal with one patient at a time.
- Collect relevant patient medication history (e.g., diabetes, coagulation issues).
- Ensure correct samples before the patient leaves the laboratory.

Analytical Phase

Enhancing quality:
- Education and training for laboratory personnel are vital.
- Labs should have standard operating procedures and use quality chemicals.
- Quality control (both internal and external) is crucial for reliability.

Internal vs. External Quality Control

Internal Quality Control: Monitors daily precision and accuracy.
External Quality Control: Maintains long-term accuracy.

Post-Analytical Phase

Processes include:
- Recording results and ensuring accuracy before reporting.
- Repeating tests if results are unexpected or samples are in doubt.

Laboratory Divisions

Main divisions include:
- Hematology
- Clinical Chemistry
- Microbiology
- Immunology
- Molecular Biology and Virology
- Histopathology

Sampling Techniques

Various sampling methods include:
- Blood, urine, stool, sputum, semen, swabs (throat, nasal, eye, wound), and various biological fluids like cerebrospinal fluid.

Blood Sampling Techniques

Vein Selection: Median cubital vein preferred for ease and flow.
Disinfection: Use 70% alcohol, allowing to dry to prevent hemolysis.
Tourniquet Application: 2-3 inches above the site.

Types of Blood Collection Tubes

Plasma Separating Tubes (PST): Contain additives like EDTA or sodium citrate; used for various tests.
Serum Separating Tubes (SST): Contain gel or silicon at the bottom for serum collection.

Plasma vs. Serum

Plasma includes fibrinogen; serum does not.
Plasma = Serum + Fibrinogen

Common Additives in Blood Tubes

EDTA: Strong anti-coagulant, used in hematology.
Sodium Citrate: Used for coagulation tests.
Heparin: Inhibits thrombin in the coagulation cascade.
Sodium Fluoride: Prevents glycolysis, used in glucose testing.

Preanalytic Interference in Samples

Common issues:
- Hemolysis: Caused by improper technique or temperature extremes.
- Icteric Samples: Yellowing due to high bilirubin levels.
- Lipemic Samples: Milky appearance due to high triglycerides.

Functions of Blood

Vital functions include:
- Substance exchange, transportation of nutrients, buffering, thermoregulation, hemostasis, and defense mechanisms.

Hematopoiesis

Formation of blood cells occurs in the red bone marrow.
Stem cells (hemocytoblasts) differentiate into various blood components.

Viscosity and pH of Blood

Plasma viscosity is 1.2-1.3 times that of water.
Whole blood viscosity is 2.4 times that of plasma.
Plasma pH ranges between 7.35 and 7.45, essential for normal body function.

Description

Explore the fundamentals of medical analysis in this introductory lecture presented by Dr. Kareman Elsaid Elabd. Learn about laboratory errors, essential laboratory units, and the importance of safety and workflow in medical testing.