Phlebotomy and Body Fluid Preservation

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Questions and Answers

What is the minimum number of CSF samples that can be processed per day?

5-10 (correct)

200

Which of the following is NOT a step in the sample collection process?

Get patient history (correct)

Transport samples

Label tubes

Select site for venepuncture

What is a critical identifier that must be on the transport sample packaging?

Date and time of collection (correct)

Patient's weight

Doctor's signature

Testing facility name

Which sample type requires the least processing per day according to the stated parameters?

Stones Signup and view all the answers

What is the main difference between plasma and serum?

Plasma is treated with anticoagulants, while serum is not. Signup and view all the answers

What is the primary use of the Yellow Top Serum Separator Tube (SST)?

For routine biochemistry tests Signup and view all the answers

Which of the following actions should NOT be performed when labeling the test tubes?

Use patient’s initials Signup and view all the answers

Which type of fluid has a daily processing limit of 5-10?

CSF Signup and view all the answers

What is the purpose of the Light Grey Top tube?

Inhibits glycolysis and alcohol dehydrogenase Signup and view all the answers

Which tube requires no gel and is specifically used for ammonia testing?

Dark Green Signup and view all the answers

What is a potential consequence of using the K-EDTA tube before the SST tube?

Artificial hypocalcaemia Signup and view all the answers

What should be avoided to reduce the risk of haemolysed samples?

Shaking the sample vigorously Signup and view all the answers

What is the result of delayed plasma separation in samples?

Increased potassium and LDH levels Signup and view all the answers

Which of the following tests would be affected by icteric samples?

Enzyme activity assays Signup and view all the answers

Which of the following describes the role of lithium heparin in the Light Green Top tube?

Prevents clot formation, allowing plasma collection Signup and view all the answers

What is a common issue with samples collected using fine gauge cannulas?

Greater incidence of haemolysis Signup and view all the answers

What is the minimum number of matching identifiers required for sample acceptance?

Two Signup and view all the answers

Which condition can be caused by incorrect container usage when collecting samples?

Reduced glucose levels Signup and view all the answers

What is one primary aim of the lecture?

To introduce phlebotomy and the preservation of body fluids Signup and view all the answers

Which of the following is NOT a step in the sample pathway?

Post-mortem examination Signup and view all the answers

Which site is commonly used for phlebotomy?

Median Cubital Vein Signup and view all the answers

Which of the following is a consideration during phlebotomy?

Applying a tourniquet Signup and view all the answers

What percentage of all diagnoses in pathology is based on sample testing?

70% Signup and view all the answers

What is the purpose of auditing in the context of body fluid sampling?

To ensure compliance with diagnostic regulations Signup and view all the answers

What does the term 'pre-analytical' refer to in the sample pathway?

Sample collection and labeling Signup and view all the answers

Which of the following is a requirement for some types of samples?

They should be sent on ice Signup and view all the answers

What did Florence Nightingale and Joseph Lister contribute to the field of pathology?

Improved knowledge of anatomy and hygiene Signup and view all the answers

Which fluid sampling approach involves puncturing the heel?

Heel prick Signup and view all the answers

Study Notes

Introduction to Phlebotomy and Body Fluid Preservation

The sampling of body fluids and their preservation is discussed.
Dr. Ross Pallett, a HCPC Biomedical Scientist (BS71638), is associated with this topic. His email address is provided: [email protected].

Preparation for the Lecture

Reflect on phlebotomy experiences.
Bring a cup of tea and biscuit.

Aim and Objectives

The lecture aims to introduce phlebotomy and the preservation of body fluids.
Topics covered include: reasons for sampling, the sample pathway, phlebotomy procedures, specimen tubes, order of draw, and auditing.

Why Sample Body Fluids?

Diagnosis is a main reason for sampling.
Monitoring treatment effectiveness is another.
Compliance with treatment plans is a further motive.
Prognosis (predicting future health) is also a factor.

Biomedical Scientists

Biomedical Scientists perform 150 million samples annually.
They are involved in 70% of all diagnoses.
They function 24/7/365.
Latest technology is used, such as the Abbott RealTime SARS-CoV-2 Amplification Reagent Kit.

Pathology: A History

Key historical perspectives on pathology are explored, focusing on how the five senses (sight, touch, hearing, smell, and taste) were used in medical assessment in the past.
Early approaches, including the four humours theory of the Ancient Greeks, are highlighted.
Landmark figures (like William Harvey) and historical advancements are explained.
The correlation between blood values and physiological conditions (as seen in the 19th century, thanks to Florence Nightingale and Joseph Lister) is referenced in the discussion.

Sample Pathway

The sample pathway consists of three phases: - Pre-Analytical: Collection, labeling, and transport of the sample. - Analytical: Diagnostic testing. - Post-Analytical: Reports and sample storage.

Common Phlebotomy Sites

The lecture mentions these sites for blood draws:
- Median cubital vein
- Cephalic vein
- Back of the hand
- Finger prick
- Heel prick

Phlebotomy Supplies

Vacuum-filled tubes, adapter, gloves, tourniquet, alcohol wipes, adhesive tape, gauze, and sharps bins are required for phlebotomy.
Note that different sample collection requirements exist (some samples need to be sent on ice, protected from light, etc.) depending on the test involved.

Correct and Incorrect Sampling

Demonstrations of correct and incorrect sampling techniques are shown.

Number of Medical Biochemistry Tests

A table shows the rate/frequency of different tests per day:
- Blood testing: 4,500 per day
- Urine testing: 200 per day
- Stool: 30 per day
- Cerebrospinal Fluid (CSF), Drainage Fluids, Ascitic/Pleural Fluids, Stones (5-10, 5, 5-10, or 1 per two weeks).

Sample Collection Procedure

Important steps of collecting samples are detailed: - Patient identification by name, date of birth, and ID. - The correct request form.

  - Selecting site and performing venipuncture, noting any bruising or other concerns.
  - Labeling procedure for samples, including matching to patient identifiers; adequate sample volume.
  - Proper tube selection and correct sample packaging (e.g., inverted tubes).
  - Prompt transport/correct storage considerations, e.g., whether the sample requires ice or protection from light; and what happens if it isn't received correctly.
  - Specific identifiers: full name, date of birth, and National Health Service (NHS) number  are required

Plasma vs. Serum

Plasma is the cell-free liquid component of blood. Anti-coagulants are used
Serum is plasma without clotting factors because it has been treated after coagulation.

Serum Separator Tube (SST)

The yellow-top tube is a serum separator tube (SST).
Inert gel is denser than serum but less dense than erythrocytes.
It's coated with spray-coated silica particles.
Routinely used for certain biochemistry tests (like U&E's, CRP, liver function, creatinine, lipid, and bone profiles).
Invert the tube 5-6 times.
Issues with incomplete barrier formation and damaged sampling probes are possible.
Gel interference can occur in drug/endocrine tests.

Red Top Tube

Red top tubes contain no additive.
Serum is obtained from centrifugation.
Alternative to yellow top where it is inappropriate.

Green Top Tube

Two types of green top tubes (light and dark) exist. Light green tubes contain lithium heparin, an anticoagulant. The blood does not clot (plasma). Invert the tube 8-10 times. Dark green tubes have no gel, so the plasma needs to be separated by centrifugation. The dark green tubes are used to test for ammonia, insulin, and aluminum.

Purple Top Tube

Anticoagulant: K-EDTA.
Whole blood is collected.
HbA1c (hemoglobin A1c) measures diabetes control.
Used to assess Cyclosporin and Tacrolimus (anti-rejection drugs), and venous carboxyhemoglobin.
Invert 8–10 times.

Light Grey Top Tube

Anticoagulant: Potassium Oxalate.
Sodium fluoride inhibits glycolysis for 5 days, and alcohol dehydrogenase.
Contains glucose, and lactate.
Invert 8-10 times.

Dark Blue Top Tube

Purified glass, no contaminating trace metals.
Used to test for copper, zinc, mercury, and selenium.

Order of Draw

Yellow-top SST tubes must be drawn before other tubes.
K-EDTA tubes are to follow.
The risk of carryover must be addressed using this order.

Interference

Haemolysed samples, icteric samples, and lipaemic samples need to be examined beforehand to avoid misleading analytical results. There are particular considerations related to potassium increases, phosphate, AST, LDH, Mg2+, bilirubin absorption, enzyme activity, and interference with common tests in blood sample analysis. Delays in separating plasma can also introduce errors (high K+, LDH). Incorrect sample containers can also lead to inaccurate glucose (no oxalate / fluoride).

Haemolysed Sample Audit

Haemolysed samples lead to misleading results.
Lab data shows issues, especially in A&E (24%).

Improvements

Training for junior doctors, use of vacutainers, and order-of-draw instruction are recommended.

Sample Acceptance

Criteria for sample acceptance, including the minimum number of matching identifiers, appropriate tubes, adequate volume, sample integrity, how rejected samples are reported.

Urines, Sweat

Urine collection method and specific tests.
Sweat chloride concentration and cystic fibrosis diagnosis.
Cystic Fibrosis gene mutation screening considerations.

Summary

The overall quality of the sample analysis is very important, and a proper pre-analytical process is essential.
Using proper sample types and correct volume are critical.
Proper sample integrity is essential.
Minimum identification criteria and the importance of order of draw (avoiding carryover) are highlighted.
Auditing completes the process.

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Description

This quiz covers key concepts in phlebotomy and the preservation of body fluids. Topics include sampling procedures, specimen handling, and the role of biomedical scientists in diagnostics. It's an essential resource for understanding how phlebotomy contributes to accurate health assessments.