HOSA Medical Assisting - Blood Specimen Collection

What are capillary blood tests?

These are frequently performed int he medical office or clinic because of the small amount of blood required, usually one to few drops.

What are capillaries?

minute blood vessels that convey blood from the arteroiles to the venules.

Why is capillary blood an ideal sample?

Blood and oxygen diffuse to the tissues and products of metabolic activity enter the bloodstrwam. It also requires a small amount of blood.

What is the most practical site to use for adults and children for capilary blood?

ring or great finger

What is the most practical site to collect capillary blood for newborns and infants?

The lateral side of the heel pad

What is a sterile lancet?

a lancet widely used for simple blood tests that require capillary blood with different blade depths needed for different circumstances (such as patients with large fingers).

What is a venous collection of blood?

when mroe than a few drops of blood are required to perform tests.

What is venipuncture/phlebotomy?

surgical puncture of a vein.

Where is the area of choice for venipuncture?

Most often is the inner arm at the bend of the elbow

What are the veins used most frequently at the area of choice for venipuncture?

median cubital vein, cephalic vein (antecubital vein)

Before obtaining a venipuncture, what is the first step any phlebotomist should do?

They must palpate the vein by applying some pressure on it with your fingertips. It will allow them to feel the direction the vein is running and the approximate size and depth of the vein.

When should blood not be obtained/drawn?

when an arm has an intravenous line inserted or from a patient that has had a mastectomy with lymph node dissection on that side.

Torniquets

help promote better palpitation and sometimes visual position of the veins.

What happens if you accidentally puncture an artery?

discontinue the venipuncture immediately, remove the needle, and apply direct forceful pressure to the puncture site for a minimum of five minutes until active bleeding has ceased.

What are signs of accidental arterial puncture?

rapidly forming hematoma, rapidly filling tube, and bright red blood

Where is the torniquet placed on the patient’s arm?

3 inches above the elbow, on the upper arm.

How long should the torniquet be on?

no more than a minute

What happens if you leave the torniquet on for more than a minute?

can lead to blood pooling at the venipuncture site, a condition called hemaconcentration, which can cause a false elevation in certain tests such as glucose, potassium, and protein-based analytes such as cholesterol.

Why should you add alcohol to the venipuncture site?

it makes the skin more sensitive to your touch and disinfects the area.

What are the venipuncture methods?

syringe and sterile needle method, the vacuum tube method, and the butterfly needle method

What size needle is used for venipuncture?

21-23 gauge. gauge must be large enough to allow blood flow through the needle without causing hemolysis.

What venipuncture method is used often?

needle and syringe

Why is the needle and syringe method used often?

it is less damaging to the tissues than the vacuum method.

What size syringe is used in the needle and syringe method?

varies according to the amount of blood needed. a 10ml to 20ml syringe is used when drawing several tubes each around 5-10 ml

Why is the vacuum method most popular?

because it is so convenient. blood specimens enter directly into the tubes for the desired tests rather than having to be transferred

What size needle is used for vacuum method?

19-23 gauge

What size needle is used for the butterfly needle method?

22 gauge

What should you do if a patient faints while seated in a chair with arm support for a venipuncture procedure?

remove the tourniquet, withdraw the needle, and hold a bandage over the puncture site. help the patient to the floor. Aromatic Ammonia Spirit can help revive the patient.

What should you do if a patient feels faint before a venipuncture procedure?

the patient should put their head down between their knees and an ice pack may be placed on the back of their neck.

What should you do if a patient says they feel faint while the venipuncture procedure is happening?

draw the patient while they are lying on the examination table.

What happens if you puncture along or parallel to the fingerprint when collecting capillary blood?

Can cause the blood to follow the pattern of the fingerprint, chaning the flow and making it more difficult to collect.

How should the puncture for capilary blood be made?

slightly off-center fromt he fleshy part of the fingertip, perpendicular (across) the fingerprints.

What is hematoma?

collection of blood just under the skin

What happens when the needle is inserted into the vein for hematoma?

it punctures the wall of the vein and blood can then leak out into the surrounding tissues. This bleeding can cause discoloration and swelling.

What happens if the vein has been punctured from the needle going completely through the vein (in one side and out the other)?

the chances of hematoma are greater

What happens if you puncture both ends of a vein during a procedure?

remove the tourniquet immediately, withdraw the needle and place gauze and pressure on the site for a minimum of three minutes. consult with the provider about applying ice, which can help with the discomfort and swelling.

What is the purpose of the BD Eclipse Blood Collection needle

It has a safety device to protect users from accidental needle injury, thereby reducing possible disease transmission.

What is the volume range found in the most common tubes for blood collection?

2 to 10 ml in capacity

What is the volume range found in blood collection tubes for pediatric patients?

2 - 3 ml

What are the red-stoppered tubes used for?

to collect whole blood that is allowed to clot so that the serum can be drawn off by centrifugation.

What is the red/gray stoppered tube used for?

has clotting activators in it as well as a gel serum separator in the bottom. During centrifugation, the gel liquiefies and travels to the center fo the tube separating the red cells from the serum.

What are the lavender-stoppered tubes used for?

contain ethylenediaminetetraacetic acid additive (EDTA) and are used for most hematology testing. usually 5 to 10 ml in size and collect whole blood specimens or plasma.

What is the gray-stoppered tubes used for?

blood glucose and blood alcohol tests and are 5 ml. contain potassium oxalate and sodium fluoride.

What are the light-blue stoppered tubes used for?

must be completely full because of the large amount of citrate. these tubes are often 5ml sixe and used for coagulation testing. test should be performed within two hours from the time it is drawn for accurate test results.

What are the green-stoppered tubes used for?

5 ml tubes that contain heparin are used to determine several chemical constituents or special hematology testing.

What is the order of drawing blood into the color-coded stoppered tubes?

special tubes (for blood cultures), light blue, red, red/gray, gold, greem, lavender, and gray.

How many times should blood in specimen tubes containing an anticoagulant be inverted immediately?

8-10 times, to prevent hemolysis

How many times should tubes with red stoppers that are plastic be inverted?

5 times and allow it to stand verticcally for 45-60 minutes to allow clotting to occur.

What can lead to inaccurate test results for venipuncture?

leaving the tourniquet on too long, not drawing blood in the correct order, collecting enough blood.

Why is collecting enough blood important?

if a blood tube has a preservative in it, as a certain amount of blood is needed for the mixture of the preservative to be correct and not cause issues with results of a patient’s potassium, magnesium, or zinc levels.

What must be kept in the log book when collecting blood specimens?

date collected

patients full name, DOB, SSN or records number

date and time sent to lab

test requested

test results

What is a centrifuge

an instrument that rotates at variable rates of speed to separate components of the blood.

How long should blood in the evacuated tube clot for serum specimens?

45 to 60 mins