Question

What is the difference between serum and plasma?

Why does it matter in the laboratory if we know if a sample is serum or plasma?

Name three tubes that can be used to collect plasma.

Explain how the needle gauge number corresponds with the needle size.

What is hemolysis and name two reasons why it may occur.

What is one test in the laboratory that is significantly affected if the specimen is

hemolyzed and WHY?

Why is it necessary to follow the order of the draw?

Answer 1

What is the difference between serum and plasma?

answer:

Plasma is blood minus cells (RBC, WBC, Platelets). Serum is plasma minus clotting elements (fibrinogen)

A key difference between plasma and serum is that plasma is liquid, and serum is fluid. Most of the components are the same for both plasma and serum, plasma contains fibrinogen which is absent in serum. Both plasma and serum can be extracted from blood with the use of a centrifuge but it’s worth noting that serum is obtained after the clotting of blood, while plasma can be obtained before the coagulation of the blood. Serum is mostly used for blood typing but is also used for diagnostic testing. Plasma on the other hand, is mostly used for blood-clotting related problems.

1)Plasma : A transparent, straw-coloured, liquid portion of the blood.  
serum: An undiluted fluid, the extracellular portion of blood.

2)plasma: Plasma is composed of serum and clotting factor.
serum:Serum is part of blood which lack clotting factor.

3)plasma: It is acquired after centrifuging blood with the anticoagulant.  
serum: It is acquired after centrifuging of coagulated blood.

4)plasma:Anticoagulant is required to obtain plasma from the blood sample.
serum: Anticoagulant is not required to separate the serum from the blood sample.

5)plasma:Consists of 55% of the total volume of blood.
serum: Less volume in comparison to plasma.

6)plasma:Comparatively easier and less time consuming than serum.
serum:Difficult to separate and is time consuming.

7)plasma:Consists of 92% water with proteins, salts, lipids, and glucose.
serum: Consists of 90% water with dissolved hormones, proteins, minerals, and carbon dioxide.

8)plasma: Contains fibrinogen.
serum: Lacks fibrinogen.

9)plasma: its density is 1.025 g/ml
serum: its density is 1.024 g/ml

10)plasma: Has a long shelf life. It can be preserved up to ten years.
serum: Has a short shelf life. It can be preserved only for a few months.

11)Plasma is the main medium for excretory product transportation.
serum: An important source of electrolytes

12)plasma: Cells are freely suspended in plasma.
serum: Cells are attached together by clot formation.

Name three tubes that can be used to collect plasma.

answer: Dark green-top tube (sodium heparin)
This tube contains sodium heparin or lithium heparin, used for the collection of heparinized plasma or whole blood for special tests

Use: Heparinized whole blood or plasma. Send plasma in a plastic transport tube labeled “Plasma, Sodium Heparin” or “Plasma, Lithium Heparin.”

Gray-top tube: Contains sodium fluoride (a preservative) and potassium oxalate (an anticoagulant).

Use: Sodium fluoride whole blood or plasma. Send plasma in a plastic transport tube labeled “Plasma, Sodium Fluoride.” Send whole blood in a gray-top tube.

Blue-top tube (also light blue-top tube): Contains sodium citrate. Be sure to use only tubes with a 3.2% sodium citrate concentration. These are easily identified by the yellow diagonal stripes on the label.

Use: Sodium citrate plasma. Send plasma in a plastic transport tube labeled “Plasma, Sodium Citrate.” Send whole blood in a blue-top tube.

Explain how the needle gauge number corresponds with the needle size.

answer:The needle gauge refers to the inner measurement or opening of the needle. Needles are routinely available in a variety of gauge sizes, including 18, 21, 23, and 25 gauge. The higher the gauge number, the smaller the needle width. On the other hand, smaller numbers denote a larger diameter or width. Selecting needles by gauge size occurs by considering skin or hide thickness and the depth of the injection.

Larger diameter gauges have thicker needle walls and are stronger and more durable. They provide for more viscous medications and support denser skin penetration. Select a lower gauge number when using a high viscosity medication. Fine gauge needles (small diameter) offer less pain for the patient and accommodate low viscosity medications. Select a higher gauge number for these types of injections. The most common needle gauges are 26 and 27. This gauge range adapts to all three types of injections--intradermal, intramuscular and subcutaneous.

What is hemolysis and name two reasons why it may occur

answer:

The abnormal breakdown of the body's red blood cells is known as hemolysis.

The presence of certain diseases can contribute to the development of this condition, which leads to hemolytic anemia. Normal red blood cells (erythrocytes) have a lifespan of about 120 days. After they die they break down and are removed from the circulation by the spleen. In some medical conditions, or as a result of taking certain medications, this breakdown of red blood cells is increased. Red cells may break down due to mechanical damage, such as from artificial heart valves or heart-lung bypass; or they may be destroyed due to defects in the cells themselves.

There are a variety of conditions which may contribute to the development of hemolysis. Certain medications, infections, and immune system responses to illness may contribute to the premature death of red blood cells. Hereditary conditions, such as sickle cell disease and G6PD deficiency disorder, may also contribute to the development of hemolysis. Exposure to poisons and toxins may adversely affect an individual’s red blood cell levels, causing a disruption of the balance of purging and production.

What is one test in the laboratory that is significantly affected if the specimen is hemolyzed and WHY?

answer: The amount of hemolysis needed to affect a test is dependent on the test being performed. In general, slight hemolysis has little effect on most tests; however, it will cause increased test results for specific tests like potassium and lactate dehydrogenase. Potassium, aspartate transaminase (AST), amylase, calcium, phosphorus, magnesium, total protein, and total and direct bilirubin showed significant changes caused by hemolysis.  hemolyzed samples are common enough to warrant a way of salvaging the sample for analysis.  A correction factor for each analyte that is significantly affected by hemolysis.

Why is it necessary to follow the order of the draw?

Answer: blood must be drawn and collected in tubes in a specific order this is known as the Order of Draw. The order of draw is recommended for both glass and plastic venous collections tubes when drawing multiple specimens for medical laboratory testing during a single venipuncture. The purpose is to avoid possible test result error due to additive carryover.

If the order of draw is not followed, then the additives in one tube can be transferred to another, causing inaccurate results and cross-contamination. Inaccurate results may lead to misdiagnosis which may prevent patients from receiving the correct treatment.  Even a slightest contamination of a certain additive from one tube to another may alter the overall results, and this could harm the life of a patient.