6. Sample Preparation and Accessioning
Laboratory Information System (LIS)
Definition: Understanding LIS technology, crucial for laboratory data management.
This system delivers laboratory patient data/results efficiently.
Automated laboratory equipment/analyzers are interfaced with the LIS system for better performance.
Benefits:
Improves laboratory productivity.
Reduces the risk of errors by directly forwarding patient data/results to the patient chart for physician review.
Functions:
Pre-analytical: Covers patient demographics including name, gender, date of birth (DOB), and physician details.
Analytical: Links specimen to test requests using barcodes.
Post-analytical: Sends reports to various departments for physician review.
Barcode Labels
Overview:
Barcodes are essential in verifying patient identity and requested tests, leading to reduced handling errors.
Types of Barcodes:
One-Dimensional (1D):
Linear barcodes requiring a laser scanner for reading.
Feature varying widths of parallel lines.
Two-Dimensional (2D):
Gaining popularity for storing extensive patient information.
Require specific printers (direct thermal or thermal transfer printer) and cannot be read by laser scanners. Instead, they need image-based scanners with charge-coupled devices or digital-camera sensors.
Specimen Accessioning Process
Definition: Accessioning is the pre-analytical process of receiving, verifying, and entering patient specimens into the LIS.
Tracking specimens in LIS aids in accurate patient identification, traceability, and workflow management.
Accessioning Steps
Specimen Receipt:
Specimens arrive from various locations (ICU, emergency department, physician's office, outpatient department).
Confirm specimen identification, specimen integrity, and check labeling against test requisitions or electronic orders.
Verification of Patient Identification:
Compare at least two patient identifiers (e.g., full name, DOB, hospital number) on the specimen label with the requisition or electronic request, ensuring they match exactly.
Reject or correct any discrepancies according to facility Standard Operating Procedures (SOP).
Assessment of Specimen Integrity:
Ensure the correct container/tube type was collected for the tests requested.
Check for adequate volume received, proper labeling, handling/transport conditions (temperature, time limits), and leaks or visible clots (test dependent).
Document unacceptable specimens and follow rejection procedures.
Review Tests Requested:
Verify tests are clearly indicated and appropriate for the specimen submitted.
Ensure additional patient information (diagnosis, medications) is included if required.
Confirm if the specimen is to be sent in-house or referred to another laboratory.
Accessioning in the LIS:
Create a new accession number (work order) in the LIS.
Enter patient demographics, requesting physician details, specimen type/source, collection date/time, specimen priority (STAT, routine, timed), and all tests requested.
Apply the generated accession label to the specimens if not previously barcoded.
Labeling and Barcoding:
Affix the LIS-generated barcoded labels to all tubes/containers.
Ensure that labels do not obstruct fill lines or other critical areas on the tube/container.
Documentation:
Document any observed preanalytical issues, including corrective actions and any reflex or associated comments.
Directing Specimens:
Route specimens to the appropriate departments for testing.
Prepare referral specimens according to shipping regulations and reference laboratory requirements.
Enter tracking information into LIS for traceability.
Storage/Retention:
Know the required storage temperatures (e.g., refrigerator/freezer).
Quality Assurance:
Monitor through audits for accurate accessioning and error tracking.
Review LIS for missing tests, incorrectly matched samples, and incomplete requests.
Preparation of Samples for Testing or Referral
Importance: Following routine pre-analytical steps ensures specimen integrity, accuracy of testing, and proper routing.
Verify specimen and requisition.
Assess specimen suitability.
Process and aliquot as appropriate (centrifuge, separate, and ensure proper labeling of aliquots).
Special handling requirements (temperature, light, chain of custody) must be adhered to.
Send to the correct department or referral lab.
Ensure optimal storage conditions.
Complete documentation and LIS entry.
Identification of Preanalytical Errors
Definition: Preanalytical errors occur before testing, such as during patient preparation, specimen collection, handling, transport, and accessioning.
Common Preanalytical Errors
Wrong patient or mislabeled specimen: Label and requisition do not match.
Specimen does not pass visual inspection: Wrong tube collected, not suitable for quality (NSQ), presence of clots.
Improper storage: Not protected from light or maintained at the correct temperature.
Delay in specimen processing beyond stability limits.
Response to Suspected Errors
Actions:
Stop testing that specimen immediately.
Determine whether recollection is required.
Document the error in LIS, including:
Patient information.
Date and time error discovered.
Description of the error (e.g., wrong tube, NSQ).
Identifying who discovered it and how.
Actions taken (e.g., recollect if applicable).
Follow SOP for non-conformance reporting.
Initiating Corrective Action
Dependent on error type:
Specimen specific: Perform necessary testing procedures (reject/recollect, recentrifugation if applicable).
Safety concerns: Investigate for potential contamination, leakage causing biohazard concerns.
Root Cause Analysis
Required for investigating repeat or significant errors.
Consider if staff training is needed, investigate instrument malfunction, unclear SOP, or workflow and communication errors.
Identification of Implausible Results
Importance: Recognizing numerous types of implausible results is critical for ensuring patient safety and treatment.
Potential Indicators:
Delta checks.
Values inconsistent with life.
Results exceeding analyzers' linearity range.
Instrument flag errors/messages.
Corrective Action for Implausible Results
Steps:
Do not report results – check for clots, hemolysis, IV dilution, lipemia, etc.
Rerun tests on the same specimen and verify calibration and quality control (QC) of analyzers.
Check for possible preanalytical errors.
If needed, request a new specimen.
Report results only once all issues are resolved and accuracy is confirmed.
Autoverification of Results
Definition: Many analyzers utilize computer-based algorithms for verifying results.
Autoverification can flag critical results, results outside reference ranges, and values that exceed analyzers' linearity ranges.
Critical Values
Definition: Critical values, or “panic values,” indicate life-threatening or medically urgent conditions.
Critical values necessitate prompt intervention; thus, results should be called out stat (urgently).
Examples of Critical Values:
Glucose < 2.0 mmol/L
Platelet count < 20 x /L (some hospitals use 10 x /L)
Positive blood culture gram stain
Hemoglobin < 70 g/L
Potassium (K+) < 2.5 or > 6.5 mmol/L
Procedure Before Notifying Critical Results
Verify the accuracy of critical values:
Repeat the test on the same specimen to rule out instrument errors, clots, and hemolysis.
Check QC results.
Check patient history for diagnosis consistency.
When calling results to a unit, provide patient identifiers and state the critical value, asking the recipient to repeat the report and stating their name/title.
Document the following for all critical reports phoned:
Date and time of notification.
Name/title of the person notified.
Method of communication.
Any actions taken.
Your initials.
Accounting for All Tests Requested/Ordered
Importance: Ensuring all testing ordered is complete and no tests are missed is crucial for accurate lab operations.
Verifications:
Verify that test orders are complete and that all specimens were received at the proper department.
Ensure that no tests remain unassigned or pending.
Validate any additional test requests and track throughout workflow (e.g., blood bank unexpected antibody detection and necessary antibody panel performance).
Upon completion of testing, confirm that all ordered tests have appropriate results and identify any tests that failed (due to instrumentation or NSQ).
Verify all accessioned tests and ensure they have assigned units and reference ranges with comments when needed (e.g., “specimen hemolyzed, interpret with caution”).
Always notify the patient area or physician when a specimen is unsuitable for testing or if a test cannot be performed; this must also be documented in LIS for traceability.