LABORATORY WORKFLOW AND LABORATORY SAFETY Flashcards
THREE PHASES OF TESTING PROCESS
Pre analysis
Analysis
Post analysis
Pre analysis
Activities that take place before testing
Test ordering and sample collection
Analysis
Activities that produce a result
Running a sample on an automated analyzer
Post-analysis
Patient reporting and result interpretation
PRE-ANALYSIS
_______of all testing errors occur in this phase
32-75%
Why is pre analysis the most critical phase?
Errors in this phase create rework or additional investigations that may cause unnecesary procedures and costs to the patients and to the healthcare system
FACTORS OF PRE-ANALYSIS
Pre-collection variables
Specimen collection
Specimen transport
Specimen processing
PRE-COLLECTION VARIABLES
Posture
Age
Gender
Exercise
Diet
Time variations
Stress
One of the most frequent errors:
selecting the wrong lab test
Test order
May be _____ or _____
_______may be made during emergency situations and should be documented given that…
electronic or in writing
Verbal requests; Official lab requests must be placed after the blood is drawn
what are add-ons
Additional tests requested on a specimen previously collected
Problems of “add-ons”
specimen is not the proper type, residual volume is insufficient, storage conditions result in analyte deterioration
There should be lab policies on the following
• If a patient refuses to have blood drawn
• If the patient was unable to be drawn
• If the patient is unavailable
• If the patient is combative
• If the patient becomes ill or faint
SPECIMEN COLLECTION
Time of Collection
Difference of ASAP and STAT collection
ASAP: do it whenever you are already free “ yes, this is important, but don’t drop EVERYTHING to do it now”
STAT: stop whatever you are doing now and collect the sample
Time of Collection
Timed specimens: OD, TID, BID, Qn (e.g. Q12, Q8, Q6, Q4, Q1)
OD:
TID:
BID:
Qn-
Once a day
Ter in die - thrice a day every
Bis in die - twice a day
Hour interval
Trough specimens:
Definition and what time of collection
reflect the lowest level in the blood; drawn 30 minutes before the drug is administered
Troughs of medication concentration occur after the drug has been broken down and metabolized by the body.
Peak vs Trough specimen
A peak is the highest level of a medication in the blood, while a trough level indicates the lowest concentration.
When are Peak specimens drawn?
shortly after medication is given
Low trough levels indicate…
fast drug clearance
Peak specimens…
reflect the highest level of drugs in the blood
Peak specimen
• Intravenous:
• Intramuscular:
• Oral:
15-30 minutes after injection/infusion
30 minutes- 1 hour after injection
1 hour after drug is ingested
• Excessively high peak levels could lead to…
toxicity and/or side effects
REASONS FOR SPECIMEN REJECTION
• Hemolysis/lipemia
• Clots present in an anticoagulated specimen
• Non-fasting specimen when test requires fasting
• Improper blood collection tube
• Short draws, wrong volume
• Improper transport conditions (e.g., no ice for blood gases)
• Discrepancies between requisition and specimen label
• Unlabeled or mislabeled specimen
• Contaminated specimen/leaking container
SPECIMEN TRANSPORT
• Transport of blood, urine, body fluids, and tissue specimens from collection site to the lab
• Excessive agitation must be avoided to minimize hemolysis
• Samples for bilirubin testing must be protected from light
• For local, onsite transport, pneumatic tube systems may be used
pneumatic tube systems pros and notes
• Rapid, efficient, and cost-effective
• Blood specimens are placed in a carrier with liners to prevent leakage and padding to ensure it remains intact
SPECIMEN PROCESSING
• Ideally, all measurements should be performed within….
45 minutes to 1 hour after collection
Specimen
______ is preferred for most biochemical determination
• Plasma or serum
•_______ is the specimen of choice due to its simplicity in collection and handling and no interference from anticoagulants
Serum
Why is serum is the specimen of choice?
due to its simplicity in collection and handling and no interference from anticoagulants
• Serum or plasma must be stored at _______if analysis is to be delayed for longer than_____
4 to 6 degrees C
4 hours
A centrifuge…
uses centrifugal force to separate phases of suspension by different densities
What to look for when buying a centrifuge?
One should look for a centrifuge with the highest possible centrifugal force and not the rotational speed
rpm:
speed in revolutions per minute
(RCF)
Relative Centrifugal Force
: radius in cm between the axis of rotation and the center of the centrifuge tube
r
Types of centrifuge position/ angle
Fixed-angle centrifugation
Horizontal centrifugation
ANALYSIS: SAMIDIR (sa middle)
• Sample Introduction and transport to cuvette or dilution cup
• Addition of reagent
• Mixing of sample and reagent
• Incubation
• Detection and calculations
• Readout and result reporting
POST-ANALYSIS
• Alarms and flags
• Flags for problem specimens
• Flags for specimens that require additional analysis with another method
• Flags for problematic results
Flags for problem specimens
Causes
• Inadequate samples
• Presence of high concentrations of interfering substances (lipids, hemoglobin)
• Flags for specimens that require additional analysis with another method
• Qualitative abnormalities of blood cells:
should prepare blood smear for further evaluation
• Flags for problematic results
If values fall outside the linear range:
automatic or manual dilution and then reanalyzed
POST-ANALYSIS
• Critical values
• Also known as
panic or alert value
• Requires rapid communication with a healthcare provider who can provide necessary medical interventions
Critical values
LAB SAFETY
• The clinical lab exposes the staff and potentially the public to a variety of hazards:
AII PEE
• Acts of Cod/force majeure
• Infectious patients
• Infectious patient specimens
• Potentially hazardous chemicals and equipment
• Ergonomic/environmental hazards
• Epidemic emergencies
LAB SAFETY
• Injuries and harmful exposures can negatively affect the lab financially
• Potential lawsuits
• Poor staff morale
• Damage to equipment
• Reputation due to bad press
• Lost workdays and wages
LAB SAFETY
…..minimize undesired outcomes
• Careful planning and compliance with the laws
• Accidents in LABORATORY are often caused by:
• Pressure to do more
• Inexperience
• Ignoring known risks
• Carelessness
• Fatigue
• Mental preoccupation
BIOLOGICAL HAZARDS
• Exposure occurs from…
•____ must be worn at all times
• All PPE must be… before leaving the lab area
ingestion, inoculation, tactile contamination, or inhalation of infectious material
PPE
removed
Hazard communication programs for employees
• Maintain inventory
• Maintain MSDS in English
• Must adhere to OSHA permissible exposure limits
• Labels must not be defaced or removed
• Information and training
• Designate responsible persons for the program
ERGONOMIC HAZARDS
• Employers must develop a program to address work-related problems that include cumulative trauma disorders (constant repetitive actions)
• Repetitive pipetting
• Keyboard use
• Resting wrists/arms on sharp edges
Ergonomic hazards
• Human error may be a causative factor when individuals…
push themselves beyond their limits and when productivity limits are too high
LABORATORY HAZARD PREVENTION
STRATEGIES
• Work practice controls
• Engineering controls
• Personal protective equipment
• General procedures/policies that mandate measures to reduce or eliminate exposure to hazard
Work practice controls
• Safety features built into the overall design of the product
• Engineering controls
• Barriers that physically separate the user from a hazard
• Personal protective equipment
WORK PRACTICE CONTROLS
Hand washing after each patient contact
Cleaning surfaces with disinfectants
Avoiding unnecessary use of needles and sharps and not recapping
Red bag waste disposal
Immunization for hepatitis
Job rotation to minimize repetitive tasks
Orientation, training, and continuing education
No eating, drinking, or smoking in lab
Warning signage
ENGINEERING CONTROLS
• Puncture-resistant containers for disposal and transport of needles and sharps
• Safety needles that automatically retract after removal
• Biohazard bags
• Splash quards
• Volatile liquid carriers
• Centrifuge safety buckets
• Biosafety cabinets and fume hoods
• Mechanical pipetting devices
• Computer wrist/arm pads
• Sensor-controlled sinks or controlled faucets
PERSONAL PROTECTIVE EQUIPMENT
• Nonlatex gloves
• Gowns and lab coats
• Masks
• Face shields
• Protective eyewear
• Eyewash station
• Chemical-resistant gloves; freezer gloves; thermal gloves
