Basic Blood Collection and Handling Flashcards
what are common reasons for specimen rejection or test cancellation?
collected in wrong tube or kept at improper temperature
QNS for analysis
improperly labelled
inappropriate container
leaked in transit
incorrect or expired transport media
incomplete or incorrect test requisition
test requisition without a specimen or specimen without test request
no specimen type or source provided
inappropriate specimen type or difficulty obtaining sample (Hemolysis, Clotted)
how many identifiers are required by the Joint Commission ?
Two patient identifiers
What should proper specimen labeling include?
Patients first and last name
unique identifying number
date, time, name of person who drew spcimen
tests requested
recommended to include specimen type or source on sample
labelling should occur in PRESENCE OF PATIENT
Is it possible to use rejected sample for testing?
if re-collection is impossible or would compromise patient care, it may be possible to provide qualified result from original specimen
with understanding of ordering physician that validity may be questionable
What volume of blood does the average adult male have? How much is plasma vs cells?
5 quarts (4.75 liters)
3 quarts (2.85 liters) plasma and 2 quarts (1.9 liters) cells
What is hemolysis and how does it occur?
thin protective membrane encasing RBCs ruptures and allows hemoglobin to escape into plasma
caused by improper handling of blood specimen, dilution, exposure to contaminants, extremes in temperature, pathological conditions
How is serum obtained?
from clotted blood that has NOT been mixed with anticoagulant
clotted blood is centrifuged, yielding serum
What two types of proteins are contained in serum?
albumin and globulin
In what color tubes is serum collected?
marbled red/gray, red and or gold top
How is plasma obtained?
blood that has been mixed with anticoagulant in collection tube
mixed blood is centrifuged yielding plasma which contains albumin, globulin and fibrinogen
either plasma or serum may be separated from red blood cells by centrifugation
What are the components of blood?
plasma, cells
blood cells are suspended in plasma made up of water and dissolved materials including hormones, antibodies and enzymes
what is the difference between plasma and serum?
plasma retains fibrinogen (clotting component)
fibrinogen is removed from the serum
what may be required for plasma specimens?
various antiocoagulants and preservatives
how are the anticoagulants used in blood collection chosen?
based on test procedure ordered
must preserve features of sable necessary to work with test method
additives NOT interchangeable
What are the 4 main steps for quality specimen for testing ?
1) preparation of paient
2) collection of sample
3) processing
4) storing or transporting
What are pre-analytical errors?
occur during specimen collection, preparation, and submission
errors are most common in which phase of testing?
pre-analytical that occur during specimen collection, preparation and submission
more common than errors arise during analytical phase during actual testing or examination
What are the most common errors affecting all types of specimens during collection?
failure to label correctly and provide pertinent information on test request
insufficient quantity of specimen or QNS
failure to use correct container or tube for specimen preservation
failure to tighteen specimen lids
How is whole blood collected for testing?
drawn into tubes containing anticoagulant
tube inverted 8-10 times after filled to ensure adequate mixing and prevent clotting
submit entire tube for testing
NOT be frozen unless instruct4ed for specific test
What are some tubes used for whole blood?
Blue top: 3.2% sodium citrate
Purple/lavender: EDTA
Green top : heparin
Yellow Top: SPS (Microbiology)
Yellow Top: ACD Solution B (genetic/chromosome analysis, flow cytometry)
Navy Blue Top: EDTA
Gray top: potassium oxalate/ sodium fluoride
How is serum specimen prepared?
specimen drawn into tube containing no additives or anticoagulants
centrifuge sample afer allowed to clot
separate serum from RBC
ensure sample has completely clotted before centrifugation
failure to allow clotting may cause fibrin clots in sample
What causes fibrin clots in serum sample and what is the potential impact?
fibrin clots interfere
problems pipetting, erroneous results especially in automated systems
What can extended clotting time of serum samples cause?
increased enzyme levels, increase in potassium and decrease in glucose levels due to prolonged exposure to RBCs
How are plasma samples prepared?
collection tubes contain anticoagulant
plasma contains fibrinogen and other clotting factors when separated from RBCs
draw whole blood specimen then centrifuge to separate plasma
What are the most common errors affecting tests utilizing serum?
failure to mix tube and allow clotting before centrigue
failure to centrifuge at correct speed or time
hemolysis
loose container lids
What are the most common errors in preparing plasma samples?
collected using incorrect additive
improper mixing with additive immediately after collection
hemolysis
incomplete filling of tube - incorrect dilution factor QNS
failure to separate plasma from cells within 30-45 minutes of venipuncture
failure to label tubes as plasma
failure to indicate type of anticoagulant (EDTA/CITRATE ETC)
What is hemolysis?
red blood cells rupture and release hemoglobin and other intracellular components into serum or plasma
hemolyzed serum or plasma is pinkish red rather than usual clear straw or pale yellow
grossly or moderately hemolyzed blood specimens may not be acceptable for testing
what kinds of analytes are adversely affected by hemolysis?
glucose, potassium, lactate dehydrogenase (LDH), cholesterol, creatinine, iron, phosphorus, calcium, and most enzymes
what are some tips for avoiding hemolysis?
20-22 gauge needle
replace vacuum tube if air leakage around needle or loss of vacuum
use clean dry sterile needles syringes and tubes
collect blood in room temperature containers
if difficulty accessign vein or tube fills slowly then collect fresh tube with good flow or select new puncture site
DO NOT remove needle from vein with vacuum tube engaged
be as gentle as possible drawing blood evenly
allow collection site to dry after cleaning - alcohol may cause contamination in a tube
DO NOT collect specimen in hematoma
allow specimen to clot completely before centrifuge
do not centrifuge prolonged period
How much blood is required for coagulation tests?
full tube of blood
ratio of anticoagulant is specific for volume of specimen (1:9)
coagulation tests not performed on short draws
What kind blood is needed for hematology and coagulation tests?
anti coagulated blood
clots will lead to errors for these tests
What may cause cloudy plasma or serum?
chronic or transient high lipid levels
patients who consume high lipid foods within 12-16 hour period preceding collection may have temporarily elevated lipid levels -> cloudy or lipemic serum
How soon after collection should hematology samples be analyzed?
within 24 hours
old samples will yield unreliable cell counts and distorted cell morphology
What is the recommended order of blood collection to avoid cross-contamination of additives and maintain sterility?
1) blood culture
2) coagulation tube (blue)
3) serum tube with our without clot activator with or without gel (red)
4) heparin with or without gel (green)
5) EDTA with or without gel separator (lavender)
6) Glycolytic inhibitor (gray)
Why should plastic or glass serum tubes containing a clot activator be drawn after coagulation testing tubes?
clot activator may cause interference with coagulation testing
What is Lithium Heparin used for in collection tubes?
tubes typically contain spray-coated lithium heparin and a gel for PLASMA separation
used for PLASMA determinations in chemistry
eliminate need to wait for clot to form
ideal for STAT procedures
and patients receiving anticoagulant therapy
What are K2 EDTA and K3 EDTA tubes used for?
whole blood hematology determinations and blood bank testing
require 8-10 inversions for through mixing of blood with ANTICOAGULANT
K2 EDTA is anticoagulant of choice in specimen collection and blood cell counting according to CLSI and ISCH
What is the anticoagulant of choice in specimen collection and blood cell counting according to CLSI and ISCH? and why?
K2 EDTA
chosen over K3 EDTA because K3 EDTA results in greater RBC shrinkage
K3 EDTA produces more significant increase in cell volume
K3 EDTA is a liquid additive and dilutes specimen
When is serum (silica) used in collection tubes?
serum determinations in chemistry, serology and blood bank
used for tests where gel-serum separator interferes with test methodology
When is heparin used in collection tubes?
either lithium heparin or sodium heparin
PLASMA determinations in chemistry
When is citrate used in collection tubes?
Routine coagulation studies
typically have 3.2% buffered sodium citrate solution
used for coagulation testing and must be filled to required volume to maintain appropriate concentration of citrate anticoagulant in plasma to be tested
When is fluoride added to blood collection tube?
glycolytic inhibitor and used for glucose determinations on plasma where delay in processing is expected
serum or plasma separator tube may be used if centrifuging is available or glucose is analyzed soon after blood draw
also used for ETOH determination
What is a red-stopper tube?
NO anticoagulant or preservative
Uses: serum or clotted whole blood
serum must be separated from cells within 45-60 minutes of venipuncture
What is marbled red/gray or red-stopper, gold top, serum-separator tube (SST)?
Contains clot activator and gel for separating serum from cells
NO anticoagulant
Use: serum
must be separated from cells within 45 minutes
serum may remain in centrifuged tube with intact barrier between cells and serum or in plastic transport tube
DONT use for therapeutic drug monitoring unless manufacturer determines serum-separator is acceptable
What is a lavender-stopper tube?
contains liquid k3 EDTA or spray coated K2 EDTA
use: EDTA whole blood or PLASMA
sample should be labelled Plasma, EDTA
What is gray-stopper tube?
contains sodium fluoride (perservative) and potassium oxalate (anticoagulant)
use: sodium fluoride whole blood or plasma
sample should be labelled “Plasma, Sodium Fluoride”
What is the blue-stopper tube?
sodium citrate (3.2%)
use: citrated whole blood or plasma
A protime (PT) test can be performed on a sample if kept unopened and uncentrifuged at room temp and delivered to lab within 24 hours
What is green-stopper tube?
sodium heparin or lithium heparin
Use: heparinized whole blood or plasma
Should be labelled “plasma, Sodium heparin”
What is yellow stopper tube ACD?
1 ml acid citrate dextrose (ACD) solution
ACD whole blood for genetic and chromosome analysis and flow cytometry
What is yellow-stopper tube SPS?
SPS (Sodium polyanethol sulfonate)
use: blood culture microbiology
blood collected in tubes may remain 2-4 hours before transfer to blood culture bottle
What is royal blue-stopper tube?
contains sodium EDTA for trace metal studies
use: EDTA whole blood or plasma
should read plasma EDTA
When and why are plastic tubes used for blood collection?
safe method
reduce potential for tube breakage and spillage
may not be appropriate for all tests
with Hemogard (BD) closure to protect personnel from blood, which might splatter when tube is opened
-rubber stopper is recessed inside plastic shield preventing exposure to blood present on the stopper
Where is the preferred venipuncture site?
antecubital fossa or back of hand
not underside of wrist
what are examples of tests requiring specimen chilling? what is the effect?
gastrin
ammonia
lactic acid
catecholamines
pyruvate
parathyroid hormone (PTH)
SLOW METABOLIC PROCESSES
What are tests requiring transportation at 37 C? What is the purpose?
cold agglutinin
cryofibrinogen
cryoglobulins
PREVENT PRECIPITATION OR AGGLUTINATION
what are tests requiring protection from light? what is the purpose?
bilirubin
vitamin A
vitamin B6
beta carotene
porphyrins
AVOID ANALYTE BREAKDOWN
what are examples of timed tests that must be collected at specific intervals?
glucose tolerance testing, cortisol, therapeutic drug monitoring
Whta is CLSI?
Clinical Laboratory Standards Institute Formerly NCCLS
What is CBC?
complete blood count
information about kinds and numbers of cells in the blood especially RBC, WBC and platelets
evaluate symptoms and diagnose conditions
What is Icterus?
presence of increased bilirubin in the blood
What is lipemia?
excess lipid in the blood
what is Prothrombin time test?
measures how long it takes blood to clot
screen for bleeding abnormalities
also monitor treatment with medication that prevents formation of blood clots
What is partial thromboplastin time PTT test?
measures time it takes blood to clot
used to screen for bleeding abormalities
