specimen handling and processing Flashcards
what are the 3 phases of laboratory process
Pre-examination / Pre-analytical
- prior to testing
Examination / Analytical
- during testing
Post-examination / Post-analytical
- after testing
who use the term “examination” instead of “analytical” when referring to the process of testing clinical samples.
the CLSI Quality Management System, QMS
where does most laboratory errors occur
pre examination phase
- begins when a patient is assessed and test is ordered
- 50-70% lab errors
true or false:
storage after testing is part of the post examination phase but can become part of the pre examination phase
true - when repeat testing or additional tests are ordered on a specimen, sometimes hours or even days later
what are the possible source of preexamination/ preanalytical error before collection
altitude
dehydrated patients
duplicate test orders
exercise/ strenuous exercise
treatments (intravenous medicine etc)
inadequate fast
incomplete requisition
medications
stress
pregnancy
smoking
wrong test ordered
what are the possible source of preexamination/ preanalytical error at time of collection
misidentified patient
antiseptic not dry
expired tube
failure to invert additive tubes properly
faulty technique
improper vein selection
inadequate vol. of lood
inappropriate use of PST or SST
incorrect
- collection tube
- needle position
- needle size
mislabeled tube
mixing tubes too vigorously
nonsterile site preparation
patient position
prolonged tourniquet application
underfilled tube
wrong collection time
what are the possible source of preexamination/ preanalytical error during specimen transport
agitation-induced hemolysis
delay in transporting
exposure to light
failure to follow temp requirements
transport method (hand vs pneumatic tube)
what are the possible source of preexamination/ preanalytical error during specimen processing
contamination (dust or glove powder etc)
delay in processing or testing
delay in fluid separation from cells
evaporation
failure to centrifuge specimen according to test requirements
failure to separate fluid from cells
what are the possible source of preexamination/ preanalytical error during specimen storage
exposure to light
temp change outside defined limits
what is specimen handing
refers to the processed involved in the:
collection
transport
processing
storage of biological specimens
what are the collection procedures
Specimens must be collected using aseptic techniques to prevent contamination.
The choice of collection tubes (e.g. anticoagulants) should align with the type of test being performed.
Timely collection is essential; specimens should be drawn at specific times as required by certain tests.
according to CLSI, what type of tubes should be placed in an upright/ vertical with the stopper up position as soon as they have been mixed and why
Nonanticoaugulant gel tube
to prevent agitation-induced hemolysis: (RBC damage and activate platelets )
what happens if there is a delay in separating the blood cells from the plasma or serum
can reult in metabolic changes in the sample (pertaining to metabolism)
according to CLSI, why should tubes be transported vertically with stopper up
upright position:
- reduce agitation that can cause RBC damage - lead to hemolysis in the specimen
- allows blood too drain away from the tube stopper to minimize the chance od aerosol (a fine mist of specimen) release when the stopper is removed
- aids clot formation in serum tubes
- prevent the clot from sticking to the stopper
what are the CLSI and OSHA guideline to place the blood specimen tubes
biohazard bag or container with a biohazard logo, liquid tight closure and slip pocket for requisition.
- The size of the bag is not standard. Depends on the order of the laboratory.
what are the CLSI and OSHA guideline to place nonblood specimens
should be leak proof containers with secure lids.
- should be tightly sealed in a cooler box.
Most common means of transporting specimens to the lab from other areas of the hospital.
Pneumatic Tube System (PTS)/ Vertical Track System
- aka PTS/ p-tube
(Automated Internal Transportation Systems)
Consists of a network of long tubes that connect to sending and receiving stations in certain lab arrears to various sections of hospitals.
Pneumatic Tube System (PTS)/ Vertical Track System
- aka PTS/ p-tube
For example:
Will be passed from sending station (e.g.nurse station) to receiving station (e.g microbiology, hematology lab)
- considered biohazard & require strict protocol to prevent potential contamination issues
-packed in leak-resistant containers and sealed in zipper-type plastic bags to contain spills
who hand delivered the blood specimens on onsite transportation of specimens
By the phlebotomist or other healthcare worker who collected blood specimens.
- Post graduate intern
- Nurses
what are the test tat are negatively affected and not affected by the PTS transport
negatively:
potassium
acid phosphate
plasma hemoglobin
lactate dehydrogenase
maintain at room temp - cryoglobulin & cold agglutinin
not affected:
albumin
alkaline phosphatase
AST
chloride
creatinine
glucose
sodium
total bilirubin
total protein
BUN
uric acid
thrombin time
WBC conc.
Involved an autonomous mobile robots (AMR)
Robot system
- Able to navigate through the facility to transport the lab specimen
what are some off-site transportation of specimens
physician offices
clinics
patient services centers
private homes
those locations^ or healthcare facility laboratories to local or regional reference laboratories
in Local Courier or Mobile Phlebotomist, how should the specimen be transported
in a leakproof of primary container/ blood tube and put it in a zip-closure plastic bag with an absorbent material (paper towels etc) and placed it in a secondary container using a plastic or metal cooler transport box. (can use Styrofoam box too)
- placed upright in a rack that sits on top of the absorbent material in the bottom of the transport box (shld be closed to avoid spills n contamination)
Out-of-Area Transportation
diagnostic specimens (blood, urine, tissue samples) that are transported out of the area by public transportation (commercial airlines, buses, trains)
what are the safety rules that must be followed in Out-of-Area Transportation
Covered by U.S
Department of Transportation (DOT)
International Air Transport Association (IATA)
regulations for transportation of infectious substances.
what are the 2 categories of infectious substances
Biological Substance Category A
- Capable of causing permanent disability or life-threatening or fatal disease in normally healthy humans
- normally healthy humans: UN 2814
- animals: UN2900
Biological Substance Category B
- Infectious substances DOES NOT meet the criteria for Category A
- UN 3373
- Lab specimens for transported for diagnostic purposes
what are the category B regulations require triple packaging requirements
what are the minimum required markings for the outer packaging container
UN 3373 label with the words “Biological Substances Category B”
Serum or plasma should be physically separated from the cells as soon as possible unless evidence is conclusive that a longer contact time will not contribute to error in test results.
CLSI Guideline GP44-A4
- on time limits
this recommends a time limit of less than 2 hours for separating serum or plasma from the cells for the following
[These specific tests MUST have the blood separated within 2 hours of collection]
Catecholamines (stress hormones)
Homocysteine (amino acid)
Lactic acid (muscle byproduc)
HIV-1 assay
LDH (enzyme test)
HBV assay
Glucose (blood sugar)
Ionized calcium
Potassium
[If blood sits too long before separation, the cells can affect the test results
This can lead to false high or low readings
Some substances in blood change quickly over time if not properly processed]
according to a 2013 article in the journal environmental and public health, how does the results of community outreach studies found that glycolysis by erythrocytes and leukocytes in blood specimen
falsely lower glucose values from 5 to 7% per hr
what is the recommended time for separating serum and plasma from the cells
a time limit of less than 2 hours
Special care is needed when handling blood specimens to protect its condition and quality.
special handling
what are the types of special handling
Body temperature specimens:
- cold agglutinin, cryofibrinogen, cryoglobulin
Chilled specimens:
- Chilling slows down the blood cell metabolite process
- Protects thermolabile (breaks down or becomes unstable when exposed to heat) analytes.
Specimens that must not be chilled:
1. coagulation specimen
Can activate clotting factors
Disrupt platelet function
- potassium
Inhibit glycolysis - pumps potassium to the cells. Hence, the potassium levels will elevate.
Light-sensitive specimens:
- Photosensitive analytes result in falsely decreased results.
- wrapped in aluminum foil to protect it from light and an amber of aliquot or transport tube
body temp:
room temp:
refrigerated temp:
frozen temp:
body temp:
36.4 to 37.6°C (37°C average)
96.8 to 99.7°F (98.6°F average)
room temp:
20 to 30°C (25°C average)
68 to 86°F (77°F average)
refrigerated temp:
2 to 10°C
35.6 to 50°F
frozen temp:
-20°C or lower (some specimens require -70°C or lower)
-4°F or lower (some specimens require -94°F or lower)
expression “on ice”
describe how a specimen shld be transported
what it rlly means is the specimen requires chilling and shld be transported in an ice slurry or cooling rack
examples of speciimens that require special handling
ACTH, adrenocorticotropic hormone
ammonia
catecholamines
gastrin
homocysteine (red top): ice slurry OK
homocysteine (gel tube): cooler rack only
lactic acid
metanephrines, plasma
PTH, parathyroid hormone
pyruvate
examples of specimens that require special handling: protect from light
beta-carotene
bilirubin
folate
Vitamin A, B2, B6, C
urine porphobilinogen
urine porphyrins
CLSI Standard C46-A2
recommends that ABG samples should NOT be placed on ice if analyzed within 30 minutes.
true or false:
if a potassium test is ordered with other analytes that require chilling, it should be collected in a separate tube
true
