Phlebotomy Book- Chapter 10

Question 1

dermal puncture is the preferred method for-

Answer 1

young patients (infants & very small children)

Question 2

dermal puncture is preferred method in younger patients because-

Answer 2

the veins are very small, & it is difficult to find a vein large enough to withstand the vacuum in evacuated collection tubes

Question 3

dermal puncture may also be used for- (3)

Answer 3

-elderly
-obese
-severely burned patients

Question 4

dermal puncture takes less time, so it is more- (3)

Answer 4

-successful
-easy to perform
-less traumatic for children

Question 5

dermal puncture may also be used as alternate method of blood collection for adults with -

Answer 5

difficult venipuncture procedures

Question 6

patients who are obese or have thin skin are often candidates for-

Answer 6

dermal (capillary) puncture

Question 7

The blood specimen obtained using dermal puncture is not entirely venous blood, instead, it is a mixture of- (4)

Answer 7

-Capillary blood
-Venous blood
-Arterial blood
-Interstitial fluid

Question 8

capillary blood is higher in-

Answer 8

glucose

Question 9

capillary blood is lower in- (3)

Answer 9

-electrolytes (sodium, potassium, chloride & calcium)
-total protein
-bilirubin making normal values (reference ranges) different

Question 10

Dermal Puncture Preparation- (6)

Answer 10

-acquire & examine the requisition slip
-greet & identify the patient
-explain the procedure
-verify any dietary restrictions
-wash your hands
-put on gloves

Question 11

main differences between venipuncture & dermal puncture- (2)

Answer 11

-site selection
-equipment assembled

Question 12

when selecting a dermal puncture site, the skin should be-

Answer 12

warm, pink, & free from scars, cuts, rashes, or bruises

Question 13

Sites to consider for dermal (capillary) puncture for children & adults- (2)

Answer 13

-use the distal region of the third or fourth finger of the hand, palmar surface of the finger, or sides of the fingertip instead of the middle of the finger
-warm the finger slightly to increase blood flow

Question 14

Sites to consider for dermal (capillary) puncture for infants- (2)

Answer 14

-use the medial or lateral plantar surface of the heel, well away from the calcaneus (heel bone) (if calcaneus is punctured, it can cause osteomyelitis (bone infection))
-never perform a dermal puncture on the heel of an infant who has begun to walk

Question 15

Sites to consider for dermal (capillary) puncture for infants less than 1 year old- (3)

Answer 15

-sides of the plantar surface of the heel are the sites of choice
-do not use the fingers because they are too small to maintain a safe distance from the bone during puncture
-If an infant has several old puncture sites, attempt to find an unused area

Question 16

do not use these sites for dermal puncture- (3)

Answer 16

-Arch of the foot
-Back of the heel
-Plantar area (bottom surface, or sole) of foot

Question 17

do not use the thumb or pointer fingerer dermal puncture because-

Answer 17

they are poor choices because the area is too thick & callused

Question 18

do not use the pinkie for dermal puncture because-

Answer 18

the bones are closer to the surface, increasing the risk of bone puncture

Question 19

actual depth of the puncture is slightly more than the lancet/device blade length because-

Answer 19

the pressure used to perform the puncture compresses the skin slightly

Question 20

lancet devices are usually set at ____ for children over 8 & adults-

Answer 20

2.2 mm

Question 21

slightly longer lancet depths may be needed for-

Answer 21

obese patients

Question 22

puncture depth should never be greater than-

Answer 22

2mm

Question 23

equipment needed for dermal puncture- (10)

Answer 23

-Requisition slip
-Alcohol prep pad
-Gauze pad
-Gloves
-Adhesive bandage or tape
-Sharps container
-Computer label
-Permanent marker or pen
-Lancet
-Microspecimen containers

Question 24

steps for planning the puncture- (3)

Answer 24

-examine the fingers
-choose a finger for the puncture
-plan to cut across the fingerprint

Question 25

select a puncture site that is warm & free from- (4)

Answer 25

-scars -cuts -rashes -bruises

Question 26

when making a puncture, plan to cut across the fingerprint, do not cut in the same direction as the fingerprint because-

Answer 26

blood tends to run in the prints or ridges instead of forming a rounded drop

Question 27

steps in performing the puncture- (5)

Answer 27

-clean the site with alcohol -allow to dry completely -hold the finger in the proper position & stretch skin tightly -position the lancet to cut across the fingerprint, rather than in the same direction as the fingerprint -puncture the finger

Question 28

improper technique during dermal puncture can cause-

Answer 28

bone infection, especially in infants

Question 29

Do not use spring-loaded devices designed for glucose monitoring for dermal puncture because-

Answer 29

these lancets produce a smaller puncture & only 2-3 drops of blood

Question 30

not allowing alcohol to dry before puncture will result in-

Answer 30

hemolysis of the blood due to contact with the alcohol

Question 31

steps to perform dermal puncture- (4)

Answer 31

-assemble the equipment, considering the patient & puncture depth -clean the site with an alcohol pad & allow the site to dry thoroughly -hold the finger (or heel) with the skin stretched tightly -use the lancet or puncture device according to the manufacturer’s direction to create the puncture

Question 32

during collection, wipe away the first drop to avoid-

Answer 32

contaminating the specimen with tissue fluid

Question 33

the first drop of blood contains- (2)

Answer 33

-interstitial fluid -damaged tissue cells

Question 34

after the next drop of blood has formed-

Answer 34

touch the open end (collection tube/scoop) of the microcollection container to the drop of blood

Question 35

while collecting the blood, gently tap the container after each drop to ensure-

Answer 35

mixing with the anticoagulant, if present

Question 36

do not “milk” the finger (massage or apply pressure moving toward the puncture site) because this will-

Answer 36

contaminate the specimen with interstitial fluid causing hemolysis or clotting

Question 37

do not scrape the container against the skin while collecting blood because this may cause the blood to-

Answer 37

hemolyze or clot before it mixes with the anticoagulant in the collection container

Question 38

it is critical to collect blood to the fill line, especially if-

Answer 38

the container has an anticoagulant

Question 39

order of draw- (4)

Answer 39

-EDTA (lavender or pink) -Heparin (green or light blue) -Sodium Fluoride (gray) -Nonadditive (red) or Serum Separator (gold)

Question 40

complications of dermal puncture- (4)

Answer 40

-Infection -Osteochondritis -Osteomyelitis -if microorganisms are present in the scar tissue from previous puncture

Question 41

infections in dermal puncture-

Answer 41

puncturing through a previously punctured site

Question 42

Osteochondritis-

Answer 42

inflammation of bone & cartilage from being punctured

Question 43

osteomyelitis-

Answer 43

inflammation of bone marrow & adjacent bone from being punctured

Question 44

collecting too much blood for dermal puncture can result in- (2)

Answer 44

-iatrogenic anemia -exsanguination

Question 45

a reason for drawing just the right amount of blood is-

Answer 45

the amount of additives in the microcollection containers are based on a specific quantity of blood

Question 46

if too little or too much blood is drawn, the ratio of blood to additive is affected, which may cause- (2)

Answer 46

-the blood to clot -affect test results

Question 47

not all patients should have a bandage applied, small children tend to put their fingers in their mouths, this puts them at risk for-

Answer 47

swallowing or choking on the bandage