Specimen Collection Pt. I Flashcards
1
Q
general considerations in specimen collection
A
- knowledge of necessary equipment & supplies
- technical skills
- strict attention to patient & specimen ID
- awareness of & adherence to institutional safety requirements
- proper specimen transport techniques (leak-proof containers, etc.)
- professionalism
- good interpersonal/communication skills
- consideration & care for the patient
2
Q
the most important part of specimen collection
A
Specimen & patient ID
- if patient ID is missed = mortal sin
3
Q
T/F:
it is okay to divulge the results of patients to friends
A
FALSE
- ensure confidentiality of results & safety of the patient
4
Q
T/F:
all body fluids are considered biohazards
A
TRUE
- wear PPE
- prevent injuries from needles/sharps
- they should be used only once
5
Q
yellow bins
A
pathologic/infectious waste
6
Q
yellow with red bins
A
Sharps disposal
- should be puncture-proof
7
Q
bins for genotoxic/cytotoxic waste
A
Black
- also for non-infectious non-biodegradable
8
Q
radioactive waste
A
orange bins
9
Q
yellow with black band/s
A
pharmaceutical, chemical waste
10
Q
non-infectious biodegradable waste
A
green bins
11
Q
samples used in the hematology lab
A
a. whole blood
- has all blood components
- usu. used for CBC, RBC/WBC cts.
b. plasma
- liquid portion of blood with anticoagulant
- top layer observed after centrifugation of blood
c. serum
- liquid expressed out of the clot
- for many CC & BB tests
12
Q
blood without anticoagulant normally starts to clot in ____________
A
5-8 minutes
13
Q
fresh blood allowed to stand for 1 hour separates into ____________ & ________
A
a. red cell-fibrin
- collects at the bottom of the tube
b. serum
- overlying liquid
*whole blood collected is allowed to clot undisturbed for (30 mins to) 1 hour at RT
14
Q
layers of anticoagulated blood after centrifugation (top –> bottom)
A
- plasma
- buffy coat
- WBC, platelets - red cell mass
15
Q
main coagulation difference of serum & plasma
A
Fibrinogen
- present in plasma, not in serum
16
Q
what to do after allowing the blood to clot?
A
Rim the clot gently from tube wall
- “rim” = “loosen”
- use wooden stick, thin plastic, or glass rod
17
Q
how many times is blood centrifuged to obtain serum?
A
2 times
- after rimming clot
- 10 mins @ 3000rpm
- pipette supernatant serum into another tube
- after 1st centrifuge
18
Q
at what temperature should serum be stored if it is used immediately?
A
RT
- 20-25C
19
Q
store at this temperature if test is delayed for 30 minutes-1 hour
A
4C
20
Q
storage at -20C is good for..
A
3 months
21
Q
temperature used for long term storage
A
-40C
22
Q
what to do for frozen specimens?
A
- thaw on the bench or in water bath (RT) before using
- invert several times to ensure homogeneity
23
Q
T/F:
it is okay to freeze thawed specimens
A
FALSE
- thawing destroys cells & analytes
- DO NOT REFREEZE; discard after
24
Q
whole blood in which fibrin is removed
A
Defibrinated whole blood
- used when serum is required urgently OR both serum & cells are required
25
instance/s when both serum & cells are required for analysis
investigation of hemolytic anemia
26
procedure to obtain defibrinated whole blood
1. place blood in a receiver
- contains a central glass rod with fused glass beads or capillary
2. whisk rod by moderate rapid rotation
* coagulation is usu. complete by 5-10 minutes --> most of fibrin is collected on the rod
27
pre-collection discrepancies
- meal within 2 hours of collection
- smoking
- physical activity within 20 minutes
- stress
- age
- gender
- pregnancy
28
tests affected when meal is taken within 2 hours of collection
a. FBS
- 6 hours fasting required
b. Cholesterol
- 12 hours fasting required
29
increased in smoking
neutrophils
30
increased when patient is under stress
WBC ct.
31
increased when doing physical activity within 20 minutes of collection
Platelet ct.
| - remedy: let patient rest for 20 minutes
32
discrepancies during collection
- diurnal variance
- posture
- prolonged tourniquet application
- excessive negative pressure when drawing blood into the syringe
33
diurnal variance
Variations at different times of the day
| - some substances in the body are high/low
34
analyte/s that is low in the morning
- serum iron
- WBC ct.
- - lowest in the morning
- - peaks at midafternoon
35
analytes affected by change of posture
Increased:
- enzymes
- proteins
- calcium
- iron
36
results in hemoconcentration
Prolonged tourniquet application
- prolonged stasis (stop) of blood flow
- increases total protein
37
results in hemolysis
excessive negative pressure
- when drawing blood into the syringe
- RBC ct. is decreased
- remedy: pull plunger in a moderate speed
38
post collection discrepancies
- insufficient/excess anticoagulant
- inadequate mixing of blood with anticoagulant
- patient or specimen ID error
- delay in transit to the lab
39
effect of insufficient anticoagulant
agglutination of RBCs
40
effect of excess anticoagulant
diluted blood sample
41
number of inversions for anticoagulant tubes
- SPS, Heparin, EDTA, NaF, red tube with clot activator
- - 8-10 times
- Citrate
- - 3-4 times
- Plain red tube
- - none
42
if blood is transported for _____________ it is to be rejected
more than 2 hours
43
necessary for most tests that require anticoagulation, macrotechniques
Venous blood
- PROS:
- - multiple & repeated exams can be performed
- - aliquots of the sample may be frozen for future reference
- - there is no variation in blood values if specimens are obtained from different veins
- CONS:
- - lengthy procedure; requires more prep.
- - technically difficult in children, obese patients, those in shock
- - hemolyzed blood affects many tests
- - hematoma may occur in & out of the vein
- - hemoconcentration may occur
44
situation:
| patient's arms are to be reserved for IV medications
- do not draw blood for any lab test
- use ankle veins CAREFULLY
- - contraindication: patients with DM (prone to clot formation)
45
hemolysis interferes with what tests?
- chemistry tests
- - enzymes
- - K
- coagulation studies
46
hematoma
clotted blood within the tissues caused by an injury to the blood vessel wall
47
tests affected by hemoconcentration
- ABG (arterial blood)
- blood counts
- blood pH (arterial blood)
- some coagulation tests
48
T/F:
| anticoagulated blood should not be used for peripheral blood smears
TRUE
- WBC, platelet counts, & ESR are unstable
- changes in platelets --> may cause clumping
- changes in WBCs --> make ID/differentiation difficult
*peripheral blood smear should be performed within 2 hours after venous blood has been obtained
49
usually used in infants less than 1 year old
Capillary peripheral blood
- when obtaining venous blood is not possible
- skin puncture is carried out with a lancet
- - discard/decontaminate after use
- CONS:
- - liable to give erroneous results
- - greater likelihood of contamination & risk of disease transmission (than venipuncture)
50
capillary blood
- free flowing
- can be arteriolar in origin
- higher Hct, RBC ct., Hgb
- total WBC & neutrophil cts. higher by 12%
- - almost 100% in children
- lower platelet counts
51
venous blood
- higher platelet counts
| - - 9-32% higher than capillary blood
52
why does capillary blood have lower platelet counts?
due to the adhesion of platelets at the site of skin puncture
53
rupture of RBCs, causing the release of Hgb into the plasma
Hemolysis
| - usu. caused by technical errors
54
hemolyzed vs. non-hemolyzed blood sample
a. hemolyzed
- clear, print can be read (background)
b. non-hemolyzed
- opaque appearance
55
hemolyzed RBCs act as ________________ in activating plasma clotting factors
tissue thromboplastin
56
steps to prevent hemolysis
- use sharp lancets
- do not squeeze/milk puncture site (dermal puncture)
- use sharp, smooth needles with large diameter (venipuncture)
- tourniquet must not be too tight
- syringe should be clean, dry, suction-gentle
- remove needle when transferring blood to tubes (except in ETS)
- mixed blood with anticoagulant gently by inversion
- if serum is needed, do not rim the clot & centrifuge until clot has completely formed
57
T/F:
| tourniquet is removed after blood is aspirated
FALSE
| - remove BEFORE blood is aspirated
58
milking
drawing blood from a very small wound
59
identify needle gauge:
white
16G
60
identify needle gauge:
pink
18G
61
identify needle gauge:
cream
19G
62
identify needle color:
20G
yellow
63
identify needle color:
21G
green
64
identify needle color:
22G
black
65
identify needle gauge:
blue
23G
66
identify needle gauge:
orange
25G
67
identify needle gauge:
purple
26G
68
identify needle color:
27G
gray
69
identify needle color:
28G
teal
70
identify needle color:
29G
red
71
identify needle color:
30G
dark yellow
72
how to invert tubes?
figure of 8 motion
73
methods of blood collection
a. skin/dermal puncture
b. venipuncture
c. arterial blood collection
74
methods of venipuncture
a. butterfly infusion
b. syringe
c. evacuated tube system
75
this venipuncture method is usu. used for pediatric patients
Butterfly infusion method
- tube is connected to an adapter/syringe
- uses "butterfly wings" with plastic tubings
76
uses vacutainer 2-way needle (multisample needle)
Evacuated tube system
- ETS
- with a plastic holder/adapter & evacuated glass tubes with a predetermined vacuum
77
method of choice for small, fragile, damaged veins
Syringe method
- veins mentioned easily collapse under vacuum pressure (ETS)
- has a barrel & plunger; needle is attached
- phlebotomist can control the vacuum
- - gently pulling back the plunger while drawing blood
78
evacuated collection tubes
- designed to fill with a predetermined volume of blood by vacuum
- various sizes available
- has color-coded rubber stoppers
- - according to the additives present
79
T/F:
| never pour blood from 1 tube to another
TRUE
| - to prevent contamination (additive carryover)
80
T/F:
| needle bore is directly related to the gauge number
FALSE
- bigger bore size, smaller gauge number
- needles are available for ETS, syringe, single draw, & butterfly infusion
81
holder/adapter is used for ____________
ETS method
82
other venipuncture equipment required
- tourniquet
- - wipe off with alcohol & replace frequently
- alcohol wipes
- - 70% isopropyl alcohol
83
medtech should not collect any specimen without this
Requisition form
- part of the medical record
- contains patient info, test to be performed
84
ways of identification
a. verbal
- have patient state his/her first & last names, date of birth
b. comparing info o patient's ID band with requisition form
* it is recommended to have at least 2 patient identifiers when collecting (CLSI, CAP, JC)
85
what to do after patient identification
Verify patient condition
- last meal
- allergies to latex
- has had previous problems with venipuncture
- - if "yes", have patient lie down
86
how to position patient's arm
- downward, slightly bent
- - so that tubes till from the bottom up
- ask patient to make a fist
87
location of the tourniquet
3- 4 inches above the antecubital fossa (puncture site)
- should be placed for 1 min only
- should be worn in a manner that it can be pulled at once
88
how to palpate the puncture area
- vertically --> determines direction, depth
| - horizontally --> determines size
89
how to clean puncture site
Concentric circles
- in to out
- allow to AIR DRY
- - not air dried will cause contamination, hemolysis
90
T/F:
| in doing the puncture, it is important to anchor the vein
TRUE
- pull the skin taut using the thumb of non-dominant hand
- - should be 1-2 inches below the puncture site
