Question

Discuss these questions: IN LABORATORY

What would be the consequence of using the wrong color tube?

What could be the consequence of using a needle that is too small, or a performing "traumatic" stick?

When can improper collection be life-threatening?

Why does the lab have to reject a blue top tube that is not filled properly?

Why do we have specific order of draw for collection?

Answer 1

# What would be the consequence of using the wrong color tube?

answer:

The blood collecting tubes are covered with a color-coded plastic cap.Most blood collection tubes contain an additive that either accelerates clotting of the blood (clot activator) or prevents the blood from clotting (anticoagulant). The color of the tube's plastic cap indicates which additives that tube contains. The tubes may contain additional substances that preserve the blood for processing in the medical laboratory. Using the wrong tube may therefore make the blood sample unusable.  

It is imperative that the phlebotomist use the tube with the correct additive to avoid erroneous patient results.

example: Green - Contains suheparin or lithium heparin used for plasma determinations in clinical chemistry (e.g. urea and electrolyte determination).   The test for lithium usually requires a serum sample. If instead of a serum tube, the phlebotomist used a tube that contained lithium heparin, the lithium result for the patient would be falsely elevated.

# What could be the consequence of using a needle that is too small, or a performing "traumatic" stick?

answer:   The gauge number indicates the bore size: the larger the gauge number, the smaller the needle bore. The 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.

With a larger gauge size comes a smaller bore and a smaller internal diameter of the collection needle. When blood cells are forced by the vacuum pressure of large volume evacuated tubes to quickly enter into the tight space of a tiny needle gauge, hemolysis may occur. Hemolysis can cause inaccurate results (slight to significant) when testing several analytes. Potassium, for example, can be falsely increased in a hemolyzed sample.

#When can improper collection be life-threatening?

Answer: Proper management of samples is critical to the accuracy and reliability of testing, and, therefore, to the confidence in laboratory diagnosis. Laboratory results influence therapeutic decisions and can have significant impact on patient care and outcomes.

mislabeling of blood samples , Consequences can be catastrophic if the labeling error goes undetected; in some cases, the patient may receive the wrong blood in a transfusion. Transfusion with the wrong blood type can cause a severe reaction that may be life-threatening. An ABO incompatibility reaction can occur if you receive the wrong type of blood during a blood transfusion.

Each year, more than 1 million blood cultures in the United States are contaminated or produce false positive results.

#Why does the lab have to reject a blue top tube that is not filled properly?

answer: blue top tube is used for Coagulation! These contain sodium citrate, an anti-coagulant that binds calcium. These tubes MUST be filled completely. Tests include PTT, PT-INR, platelet function assays, and fibrinogen.

A light-blue top tube (a blood collection tube containing 3.2% sodium citrate) that will be used for coagulation testing must be filled to completion. Under-filling the tube changes the ratio of blood to anticoagulant. This can affect the accuracy of coagulation tests that are performed using this specimen.

#Why do we have specific order of draw for collection?

Phlebotomists must collect blood samples using collection tubes in a specific order while performing venipuncture on patients to avoid cross-contamination of the various additives between tubes. This process is known as the order of draw.

Blood collection tubes must be filled in a specific sequence to minimize contamination of sterile specimens, avoid possible test result error caused by carryover of additives between tubes, and reduce the effect of microclot formation in tubes.

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.

• When blood tubes are collected out of order, there may be carryover of anticoagulants or additives, causing erroneous results.
• Example:  A lavender tube drawn before an SST tube may give elevated potassium results.