Lesson 4: Specimen Handling and Processing Flashcards by zy g

46-68 % of all errors for laboratory samples

Pre-analytical errors

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How to prevent errors in laboratory samples?

Follow proper collection procedures

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Most serious, potentially most dangerous pre-analytical error

Improper patient identification

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2 Kinds of Handling

Routine handling (mixing, transport at RT) and special handling (body temp., chilled, light-sensitive specimen)

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2 Kinds/Types of Processing

centrifugation, aliquot preparation

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Physiological variables that may affect laboratory results

Age
Altitude
Dehydration
Diet
Stress
Drug therapy
Exercise
Fever
Gender
Diurnal or Circadian variations
Position
Pregnancy
Smoke
Temperature

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POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION

Misidentified patient
Antiseptic not dry (for blood alcohol testing: DO NOT use alcohol as antiseptic)
Expired tube
Wrong collection time
Incorrect needle position
Incorrect needle size
Mislabeled tube
Nonsterile site preparation
Incorrect collection tube

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POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION (1.2)
:Additive and test/department of color LIGHT BLUE collection tube

Sodium citrate; Coagulation studies (PT, APTT)

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POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION (1.2)
:Additive and test/department of color LAVENDER collection tube

EDTA; Hematology (CBC, platelet ct)

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POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION (1.2)
:Additive and test/department of color GREEN collection tube

Heparin (Lithium heparin, Sodium heparin); Chemistry (Blood gas analysis, electrolytes)

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POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION (1.2)
:Additive and test/department of color GOLD/ORANGE collection tube

Clot activator; Chemistry

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POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION (1.2)
:Additive and test/department of color RED PLASTIC collection tube

Clot activator; Chemistry

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POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION (1.2)
: Additive and test/department of color GRAY collection tube

Sodium fluoride and potassium oxalate, sodium fluoride and EDTA, sodium fluoride; Chemistry (glucose)

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Give the additive/s and department of RED (GLASS) tube

None; Chemistry, Blood bank, Serology/Immunology

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Give the additive/s and department of RED LIGHT GRAY and CLEAR tube

None; None

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Give the additive/s and department of RED/BLACK (TIGER) and GOLD tube

Clot activator and gel separator; Chemistry

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Give the additive/s and department of GREEN/GRAY and LIGHT GREEN tube

Lithium heparin and gel separator; Chemistry

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Give the additive/s and department of GREEN tube

Lithium heparin and Sodium heparin; Chemistry

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Give the additive/s and department of PINK tube

EDTA; Hematology

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Give the additive/s and department of ORANGE and GRAY/YELLOW tube

Thrombin; Chemistry

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Give the additive/s and department of ROYAL BLUE tube

None, EDTA, Sodium Heparin; Chemistry

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Give the additive/s and department of TAN tube

EDTA; Chemistry

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Give the additive/s and department of YELLOW

Sodium polyanethol sulfonate (SPS); Microbiology

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Give the additive/s and department of YELLOW pt. 2

Acid citrate dextrose (ACD); Blood bank; immunohematology

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CORRECT ORDER OF DRAW

1. Sterile blood culture tubes - Yellow 2. Coagulation tubes - Light blue 3. Serum tube/Glass Plain tube - Red 4. Heparin tube - Green 5. EDTA tube - Lavender/Purple 6. Anti-glycolytic tube/ Fluoride - Gray

Tube inversions

1. Yellow or bottle - 8-10x 2. Light blue - 4x 3. Red - None 4. Red (Plastic tube) and Gold - 5x 5. Green - 8x 6. Lavender/purple - 8x 7. Gray - 8x

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION Incorrect volume of blood in the tube

underfilled tube

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION Less blood means

Dilutional effect

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION Too much blood means

Blood clots

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION - Underfilled tube Most critical

Citrate tubes for coagulation stuies

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION Blood to anticoagulant ratio

9:1

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION What do you do if the tube is only partially filled?

Collect blood again

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION Changing from supine to standing leads to too much pressure

Hemoconcentration

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION Remaining supine for a long time leads to

Hemodilution

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION Increases the intravascular blood

Tourniquet

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION - Prolonged tourniquet application Ideal inches to the site

3-4 inches above the site

POSSIBLE SOURCES OF PREANALYTICAL ERROR: AT THE TIME OF COLLECTION Prolonged tourniquet application leads to

Hemoconcentration

POSSIBLE SOURCES OF PREANALYTICAL ERROR: LABELING SPECIMENS Specimens must be labeled:

- Immediately after collection - before dismissing an outpatient - before leaving the room of an inpatient

POSSIBLE SOURCES OF PREANALYTICAL ERROR: LABELING SPECIMENS Reverification of patient information before labeling

- show the labeled tube to the patient or - have the patient initial or sign a document stating that they were shown the labeled tube and confirmed that the information was correct

POSSIBLE SOURCES OF PREANALYTICAL ERROR: LABELING SPECIMENS - LABEL POSITIONS - patient's name must be read from left to right - label to cover the manufacturer's label leaving a gap from the top of the label to the colored cap

Regular Vacutainer Label Placement

POSSIBLE SOURCES OF PREANALYTICAL ERROR: LABELING SPECIMENS - LABEL POSITIONS - patient's name from left to right - label directly underneath the colored top - no gap between the colored top and the label

Micro Label Placement

POSSIBLE SOURCES OF PREANALYTICAL ERROR: DURING SPECIMEN TRANSPORT

* Agitation-induced hemolysis * Delay in transporting * Exposure to light * Failure to follow temperature requirements * Transport method (e.g., hand vs. pneumatic tube

POSSIBLE SOURCES OF PREANALYTICAL ERROR: DURING SPECIMEN PROCESSING

* Contamination (e.g., dust or glove powder) * 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 * Incomplete centrifugation * Mislabeled aliquot * Multiple centrifugations * Rimming of clots

POSSIBLE SOURCES OF PREANALYTICAL ERROR: DURING SPECIMEN STORAGE

* Exposure to light * Temperature change outside defined limits

- Mixing of tubes - Transport - Adherence to time limits set for delivery of specimen to the laboratory

Routine Handling

MIXING TUBES BY INVERSION: Additive tubes inversions:

3 to 10 gentle inversions (depending on the type of tube and additive)

MIXING TUBES BY INVERSION: - even distribution of additive - minimizes hemolysis

Gentle Inversion

MIXING TUBES BY INVERSION: Vigorous mixing can cause

Hemolysis

MIXING TUBES BY INVERSION: NOT performed on hemolyzed specimens:

potassium, magnesium, and most enzyme tests

MIXING OF TUBES WITH ADDITIVES: Inadequate mixing of anticoagulated tubes leads to

- Microclot formation - erroneous test results, hematology studies

MIXING OF TUBES WITH ADDITIVES: Inadequate mixing of gel separation tubes leads to

clotting may be incomplete

MIXING OF TUBES WITH ADDITIVES: Tubes that should not mix because hemolysis might take place

Non-additive tubes

TRANSPORTING SPECIMENS: This can: - hemolyze specimens - activate platelets and affect coagulation tests - break glass tubes

Rough handling and agitation

TRANSPORTING SPECIMENS: - to reduce agitation - aid clot formation in serum tubes - prevent contact of the contents with the stopper

Tubes should be transported stopper up

TRANSPORTING SPECIMENS: - self-sealing plastic bag - 2 compartments - warp in absorbent package material - with biohazard logo

Primary container

TRANSPORTING SPECIMENS: - light-tight closure plastic bags - with slip packet paperwork (requisition form) - with a visible biohazard logo - per patient

Transport bag

TRANSPORTING SPECIMENS: 2 compartments in the primary container

1. Sample 2. Requisition form

TRANSPORTING SPECIMENS: - placed in a bag or box

Secondary container

TRANSPORTING SPECIMENS: Multiple samples from one patient =

One bag

TRANSPORTING SPECIMENS: ◦ Samples from different patients should not be placed in

the same plastic bag

TRANSPORTING SPECIMENS: Large number of samples:

place in a rack

TRANSPORTING SPECIMENS: Place the rack in

a bag or leak-proof box

TRANSPORTING SPECIMENS: ◦ System that propels cylindrical containers through networks of tubes by compressed air or by partial vacuum ◦ More traumatic ◦ Faster delivery ◦ Bagged sample in a padded container ◦ specimens should be protected from shock and sealed in zipper-type plastic bags to contain spills

Pneumatic tube system/Pneumatic tube transport (PTT)

TRANSPORTING SPECIMENS: Robot specimen transportation system called the RoboCourier® Autonomous Mobile Robot.

Automated Transportion Systems

TRANSPORTING SPECIMENS: Too hot or freezing temp can cause

rupture of RBCs

TRANSPORTING SPECIMENS: Separate this from cells before transport

serum/plasma

TRANSPORTING SPECIMENS: Samples in the car should be placed

in a cooler

MEDICO-LEGAL TRANSPORT: documentation of proper sample identification from the time of collection to the receipt of laboratory results

Chain of Custody

MEDICO-LEGAL TRANSPORT: Chronological documentation or paper trail

◦ Collection ◦ Transfer ◦ Receipt ◦ Analysis ◦ Storage ◦ Disposal of the sample

MEDICO-LEGAL TRANSPORT: ensures that any results reported relate beyond all reasonable doubt to a particular individual

chain of custody

MEDICO-LEGAL TRANSPORT: consists of: - special draw kit - chain of custody form

Blood Alcohol Testing

MEDICO-LEGAL TRANSPORT: ◦ Documentation that samples were collected from the correct individuals ◦ Pictures of the child, alleged mother or father

Paternity Testing

SPECIAL HANDLING: is needed when handling blood specimens to protect their condition and quality

Special Care

SPECIAL HANDLING: Special handling of specimen considerations

1. body temperature 2. chilled specimen 3. light-sensitive specimen

SPECIAL HANDLING: Specimens transported and stored at body temp

Warming of samples (37 degree celsius)

SPECIAL HANDLING: Specimens precipitate at cold temperature

- Collect in a pre-warmed (37 C) tube - Transport at normal body temp 37 C - Use heat/warming blocks during transport - Wrap in an activated heel warmer

SPECIAL HANDLING: Specimens specimens precipitate at cold temperature Examples of specimens keep at 37 degrees celsius

- Cold agglutinins - Cryoglobulin - Cryofibrinogen

SPECIAL HANDLING: for specimens that can withstand higher than 37 C

Wrap in an activated heel warmer

SPECIAL HANDLING: CHILLED SAMPLES slows the metabollic process

Chilling (4 C, 2-8 C)

SPECIAL HANDLING: CHILLED SAMPLES Submerged in _________ during transport, tested immediately or refrigerated

in crushed ice and water slurry

SPECIAL HANDLING: CHILLED SAMPLES Tests that require chilling of specimen

◦ Adrenocorticotropic hormone (ACTH) ◦ Acetone ◦ Ammonia ◦ Acid Phosphatase ◦ Catecholamines ◦ Lactic acid ◦ Parathyroid hormone ◦ pH/blood gases

SPECIAL HANDLING: CHILLED SAMPLES Chilling off uncentrifuged blood will

elevate potassium

SPECIAL HANDLING: CHILLED SAMPLES Chilled specimen

- Blood Specimen Transporter - Submerged in crushed ice and water slurry

HANDLING OF LIGHT-SENSITIVE SPECIMEN: - decreases up to 50% after 1 hr of light exposure - wrap in aluminum foil - light-blocking, amber tubes - amber containers for urine specimen - light-blocking secondary transport containers

Bilirubin

HANDLING OF LIGHT-SENSITIVE SPECIMEN: Other light sensitive analytes:

◦ Folic acid ◦ Carotene ◦ Vitamins B2, B6, B12, C ◦ Urine porphyrins ◦ Urine porphobilinogen

Examples of specimens that require special handling: Chill in Crushed Ice Slurry

- Adrenocorticotropic hormone (ACTH) - Acetone - Angiotensin-converting enzyme (ACE) - Ammonia - Acetone - Catecholamines - Gastrin - Glucagon - Homocysteine - Lactic acid - Parathyroid hormone (PTH) - pH/blood gas (if indicated) - Pyruvate - Renin

Examples of specimens that require special handling: Protect from Light

- Bilirubin - Carotene - Red cell folate - Serum folate - Vitamin B2 - Vitamin B6 - Vitamin B12 - Vitamin C - Urine porphyrins - Urine porphobilinogen

Collected specimens are transported to the central processing triage for screening and prioritizing

Blood specimen processing

BLOOD SPECIMEN PROCESSING: specimens are:

1. Identified 2. Logged or accessioned 3. Sorted by department and type of processing 4. Evaluated for specimen suitability

SPECIMEN SUITABILITY: most frequent reason for specimen rejection

Chemistry ◦ Hemolysis ◦ Insufficient amount of specimen QNS Hematology ◦ Clotting

◦ Specimen is not identified properly ◦ Inadequate volume/ Insufficient specimen (QNS) ◦ Hemolysis ◦ Wrong tube ◦ Tube used is outdated ◦ Clots in anticoagulated tubes (improper mixing) ◦ Contaminated specimen ◦ Incorrect collection time ◦ Exposure to light (bilirubin) ◦ Testing time limits not followed ◦ Delay or error in processing

Specimen Rejection Criteria

DELIVERY TIME LIMITS: routine blood specimens should arrive at the laboratory within

45 minutes of collection

DELIVERY TIME LIMITS: Specimens that require separation of the serum or plasma from the cells should be centrifuged

within 1 hour

DELIVERY TIME LIMITS: These specimens drawn in EDTA tubes should not be centrifuged

Hematology test specimens

DELIVERY TIME LIMITS: maximum time limit for separating serum and plasma from the cells is

2 hours from time of collection

DELIVERY TIME LIMITS: Serum tubes that have not been spun within 2 hours or refrigeration of serum tubes before centrifugation will:

◦ Increase potassium, creatinine, phosphorus, LDH, lactic acid, Lipids, total protein ◦ Decrease glucose, ionized calcium, chloride, and CO2 ◦ Prompt delivery and separation minimize glycolysis ◦ sodium fluoride prevents glycolysis

GEL-BARRIER TUBES: completely clotted before centrifugation

Non-additive and gel-barrier serum tubes (SSTs)

GEL-BARRIER TUBES: can be centrifuged right away

Heparin gel-barrier tubes (PSTs)

GEL-BARRIER TUBES: Specimens in gel-barrier tubes do not require

manual separation

GEL-BARRIER TUBES: order of layers in gel-barrier tubes

serum, separator gel, blood clot

TIME LIMIT EXCEPTIONS: means priority

STAT or "medical emergency"

TIME LIMIT EXCEPTIONS: Prepared within 1 hour from collection

Blood smears from EDTA

TIME LIMIT EXCEPTIONS: - Analyzed within 6 hours - Stable for 24 hours (RT)

CBC (EDTA)

TIME LIMIT EXCEPTIONS: Analyzed within 4 hours

CBC in micro-containers

TIME LIMIT EXCEPTIONS: Tested within 4 hours( RT) Within 12 hours (refrigerated)

ESR (Erythrocyte sedimentation rate (EDTA)

TIME LIMIT EXCEPTIONS: - Stable up to 6 hours at RT - 72 hours if refrigerated

Reticulocyte Counts (EDTA)

TIME LIMIT EXCEPTIONS: - Stable for 24 hrs (RT) - 48 hrs (refrigerated)

Glucose test in sodium fluoride tubes

TIME LIMIT EXCEPTIONS: 24 hours

Prothrombin time (PT)

TIME LIMIT EXCEPTIONS: 4 hours

Partial thromboplastin time (PTT) test

TIME LIMIT EXCEPTIONS: Separated from cells within 15 mins.

Blood Ammonia

TIME LIMIT EXCEPTIONS: - Perform ASAP - Plasma stored at 4 C for 48 hrs

Molecular test specimens

SPECIMEN PROCESSING: after specimen collection and before centrifugation

Precentrifugation

SPECIMEN PROCESSING: when the specimen is in the centrifuge

centrifugation

SPECIMEN PROCESSING: after centrifugation and before the removal of serum or plasma

post centrifugation

Allow blood in nonadditive, clot activator, and gel-containing tubes used for serum tests (e.g., SSTs) to clot for the serum to separate from the cells

precentrifugation

must not be centrifuged until clotting is complete

precentrifugation

PRECENTRIFUGATION: happens when clotting is incomplete

latent fibrin formation may form a clot in the serum after centrifugation

PRECENTRIFUGATION: complete clotting on how many minutes and room temperature?

30 to 60 minutes at room temperature (22° to 25°C)

PRECENTRIFUGATION: Specimens that take longer to clot

◦ patients on anticoagulant medications, heparin or warfarin (e.g., Coumadin) ◦ from patients with high WBC counts ◦ chilled specimens ◦ from patients with coagulopathies (bleeding disorders)

PRECENTRIFUGATION: Tubes with clot activators clots within:

within 30 minutes

PRECENTRIFUGATION: Tubes with thrombin clots within:

within 5 minutes

PRECENTRIFUGATION: Complete clotting can be determined by

tilting or inverting the tube gently

PRECENTRIFUGATION: Rimming the tube with an applicator stick to release the clot from the walls of the tube is a potential source of

hemolysis and contamination

is a process in which centrifugal force is used to separate solid matter from a liquid suspension

Centrifugation

a machine that spins blood and other specimens at a high number of revolutions per minute (rpm) or centrifugal force to separate serum or plasma from cells

Centrifuge

CENTRIFUGATION: - depends on the speed of rotation (revolution per minute) and the radius of the rotor head - Expressed as gravity (g) or RCF - Most specimens are centrifuged for

Relative centrifugal force

CENTRIFUGATION: Most specimens are centrifuged for

-15 minutes at 750 g to 1000g -10 minutes at 1000 g

CENTRIFUGATION: types of centrifuge

- refrigerated - floor-top model - table top (benchtop) model

CENTRIFUGATION: Removing the stopper will result to

◦Aerosol formation ◦pH changes (loss of CO2 which can increase pH) ◦Evaporation (leads to concentration of analytes) ◦Contamination

CENTRIFUGATION: drop of ______, interferes with ________ results

sweat; electrolyte

CENTRIFUGATION: _______ from gloves, interferes with ________ determination

powder, calcium

CENTRIFUGE OPERATION: equal-size tubes with equal volumes of specimen must be placed opposite one another in the centrifuge

balanced tubes in a centrifuge

CENTRIFUGE OPERATION: break specimen tubes, ruin specimens, and cause the contents to form aerosols

unbalanced centrifuge

CENTRIFUGE OPERATION: - can cause hemolysis and analyte deterioration - alter test results

repeated centrifugation

CENTRIFUGE OPERATION: processed in a temperature-controlled refrigerated centrifuge

specimens requiring chilling

CENTRIFUGE MAINTENANCE: Regular maintenance should be scheduled according to manufacturer instructions to check the ____

balance, braking mechanism, centrifuge speed, and timer

CENTRIFUGE MAINTENANCE: check the speed using a _____________, an instrument designed for measuring rpm

strobe light or a tachometer

CENTRIFUGATION: centrifuge without delay

Tubes containing anticoagulants

CENTRIFUGATION: tubes used for STAT chemistry tests

green top heparin tubes to save time; reduce turn-around time (TAT

CENTRIFUGATION: containing gel tubes -to maintain specimen stability after centrifugation

PSTs or other heparin

- Be careful not to disturb the specimen (can cause resuspension in tubes without separator gel - No RBCs should be visible in the serum or plasma - serum or plasma should be separated from the cells as soon as possible - Specimens in gel barrier tubes do not normally require manual separation - physical barrier prevents glycolysis

POST CENTRIFUGATION

POST CENTRIFUGATION: serum on gel barriers can be stored up to

48 hours to 4°C

How to remove the stopper?

Pull straight up to prevent the release of aerosol; wear face shield

AFTER CENTRIFUGATION: pale yellow

normal

AFTER CENTRIFUGATION: dark yellow means

Icteric (icteric serum); high bilirubin

AFTER CENTRIFUGATION: cloudy, turbid

Lipemic (lipemic serum); high lipids

AFTER CENTRIFUGATION: - pink, red - Patient’s underlying condition ◦errors in specimen collection

Hemolysis (Hemolyzed serum); high potassium, ammonia, phosphate, enzymes

a portion of a specimen used for testing

Aliquot

method of dividing or separating specimens into separate containers

Aliquoting

prepared when multiple tests are ordered on a single specimen

Aliquot Preparation

* Use a disposable transfer pipette * Never put serum and plasma, or plasma from specimens with different anticoagulants, in the same aliquot tube * Aliquot tube should be covered or capped as soon as it is filled

Aliquot Preparation

Pouring the serum or plasma into aliquot tubes is not recommended because it increases the possibility of

aerosol formation or splashing

Required Protective Equipment Worn when Processing Specimen

-OSHA Act RA 11058 ◦◦Gloves ◦◦Laboratory gowns/coats ◦◦Masks ◦◦** Goggles/face shield