Laboratory Operations
Build reliable bench habits: check specimens, review controls, judge method performance, work safely, release and correct results, and link each instrument's principle to its signal and interferences.
Steps
- Locate an error in the preanalytic, analytic, or postanalytic phase
- Verify patient and specimen identity before testing or giving a result
At the bench Check specimen identity and suitability before analysis
- Decide whether a clot, short fill, wrong tube, or delay makes a specimen unsuitable
- Recognize high potassium with low calcium as a sign of EDTA carryover
- Recognize when fluid from an infusion line has diluted or spiked the specimen
At the bench Check specimen identity and suitability before analysis
- Distinguish collection hemolysis from possible hemolysis in the patient
- Distinguish a patient-related interference from a collection problem
- Check identity, contamination, and the run behind a failed delta check before release
At the bench Check specimen identity and suitability before analysis
- Choose release, repeat, comment, or recollection from the specimen checks and QC
- Communicate a critical result with identifiers, units, and confirmed receipt
- Call an established critical result before continuing routine work
- Correct a reported error, keep both reports, and notify the care team
At the bench Check specimen identity and suitability before analysis · Communicate a critical result and confirm receipt · Correct a report while preserving the original result record
- Control statistics13 min
- Calculate the mean of control measurements
- Calculate standard deviation from stated control limits and state its unit
- Calculate coefficient of variation from a mean and standard deviation
- State the share of control results expected within 1, 2, and 3 SD of the mean
- Recognize a shift, trend, or random scatter on a Levey-Jennings chart
- Tell a 1-2s warning from a 1-3s rejection
- Tell a 2-2s violation from a 1-3s violation
- Tell a 2-2s violation from a 4-1s violation
At the bench Review QC before releasing results
- Recognize an R-4s violation within one run
- Recognize a 10x violation in consecutive same-side controls
- Match a QC shift, trend, or random error to its likely causes
At the bench Review QC before releasing results
- After QC fails14 min
- Confirm corrective action before accepting the next QC run
- Decide which patient results need review after rejected QC
- Set a new control lot's mean from its crossover runs and its SD from the established CV
At the bench Review QC before releasing results
- Calculate a sigma metric with compatible error, bias, and imprecision units
- Tell method agreement from a high correlation coefficient
- Test proficiency samples through the routine patient workflow
At the bench Check method precision and agreement against acceptance limits
- Check operator, reagent, device, and control readiness before point-of-care testing
- Match a test's CLIA complexity to the certificate that covers it
- Choose safe packaging and handling for a specimen shipment
At the bench Check operator, reagent, and control readiness for point-of-care testing
- Choose PPE and handling controls for a task's splash, sharps, or aerosol risk
- Choose the immediate response to a blood or body-fluid exposure
- Use the SDS and hazard label to choose chemical handling and spill precautions
- Choose the required response to a fire or equipment emergency
At the bench Choose protective equipment for the work at hand · Respond to an exposure, spill, or fire using the local procedure
- Making up solutions15 min
- Calculate molarity or reagent mass using the solute molar mass
- Calculate normality for the stated reaction
- Calculate a percent solution on its stated mass/volume, volume/volume, or mass/mass basis
- Calculate the stock volume required for a target solution
- Convert between compatible mass, volume, and amount concentration units
- Calculate the median of an ordered set of results
- Convert percent transmittance to absorbance
- Calculate diagnostic sensitivity against the reference classification
- Calculate diagnostic specificity against the reference classification
- Calculate positive and negative predictive values
- Verify temperature at the working sample position
- Follow the to-contain or to-deliver marking on volumetric equipment
- Choose a pipette type for the volume and for viscous, volatile, or foaming liquids
- Calculate delivered volume from water mass and the stated conversion factor
At the bench Perform and document required equipment checks
- Choose a vessel and cleaning process that will not alter the analyte
- Tell balance readability from repeatability measured with mass standards
- Calculate relative centrifugal force from radius and rotational speed
- Choose resistivity, organic-carbon, or plate-count checks for the water an assay needs
At the bench Perform and document required equipment checks
- Trace a photometric fault to the lamp, wavelength selector, cuvette, or detector
- Predict the effect of stray light on a high-absorbance measurement
- Calculate a concentration from absorbance with the fitted standard curve
- Match an atomic-absorption interference to its mechanism
At the bench Review a calibration curve before using a measurement method
- Predict elution order from how compounds interact with the stationary phase
- Predict protein migration from buffer pH relative to the isoelectric point
- Check the internal-standard response before releasing an LC-MS result
- Choose an osmometry principle that detects volatile solutes
At the bench Review a separation pattern and its method controls · Review electrolyte results and related calculations for consistency
- Explain why an indirect ion-selective electrode (ISE) can show pseudohyponatremia
- Distinguish measured blood-gas values from calculated values
- Distinguish excitation-driven fluorescence from chemical light production
- Distinguish turbidimetric attenuation from nephelometric scatter
At the bench Review electrolyte results and related calculations for consistency
- Choose the flow-cytometry control for gate placement, spillover, or autofluorescence
- Calculate an absolute subset count using the correct parent population
- Report a low result within the method's detection and quantitation limits
- Choose an extraction method for a DNA, RNA, or cell-free nucleic acid target
- Accept or reject a nucleic-acid extract using A260/A280, integrity, and amplifiability
- Choose endpoint, real-time, digital, or RT-PCR for the target and for quantitation
- Locate the failed step of a molecular test from where each control is added
At the bench Prepare a molecular run with the required controls
- Predict how stringency changes nucleic-acid probe specificity
- Limit a negative sequencing report to the regions and variant types the assay covers
- Calculate cost per reportable result with a consistent denominator
- Choose the next CBC check from flags, red cell indices, lipemia, or cold agglutination
- Match a coagulation measurement principle to its likely interference
- Recognize when an automated identification or susceptibility result needs confirmation
- Tell course attendance from documented competency assessment
At the bench Resolve analyzer flags before releasing a blood count · Review coagulation results and identify the next laboratory check · Reconcile organism identification with specimen source and observed growth