Seroim lab prelim comprehensive

Serum

Liquid supernatant obtained after complete blood coagulation, lacking fibrinogen and clotting factors II, V, and VIII.

Plasma

Liquid supernatant obtained from anticoagulated blood containing fully dissolved fibrinogen and active clotting factors.

Packed Red Blood Cells

Concentrated erythrocytes remaining at the bottom of an anticoagulated tube after centrifugation, used as indicator cells in agglutination assays.

Hemolysis

Physical rupture of red blood cell membranes releasing free hemoglobin into serum or plasma, turning supernatant pink to deep red.

Lipemia

Milky turbidity in specimen supernatant caused by elevated light-scattering lipoprotein particles (chylomicrons).

Icterus

Deep yellow-green specimen discoloration caused by elevated bilirubin, absorbing light in the 450-500 nm range.

30 Minutes

Minimum required standing time at room temperature for non-anticoagulated blood to form a complete clot before centrifugation.

3000 RPM

Centrifuge speed setting used in the student laboratory to generate approximately 1,066 x g of centrifugal force.

1,066 x g

Relative centrifugal force (RCF) required to separate serum or plasma from cell mass securely without causing cell lysis.

Rimming

Process of gently pushing down on a clot with an applicator stick to express trapped serum and remove fibrin strands clinging to tube walls.

Buffy Coat

Thin whitish middle layer formed after centrifuging anticoagulated blood, containing white blood cells and platelets.

2°C to 8°C

Refrigeration temperature required for short-term storage of serum or plasma (up to 48 hours) and for preserving RBCs.

-20°C

Standard freezer temperature used for long-term storage of serum and plasma specimens for up to 1 year.

-70°C to -80°C

Ultra-low freezer temperature range required for long-term biobanking of delicate serum analytes and biomarkers.

Soret Band

Specific light absorbance peak of free hemoglobin around 415 nm that causes optical interference in spectrophotometric assays.

Pre-analytical Phase

Testing stage encompassing patient prep, collection, processing, and storage, accounting for 60% to 70% of laboratory errors.

QNS

Quantity Not Sufficient; specimen rejection criterion where tube draw volume is below minimum needed for testing.

56°C for 30 Minutes

Heat inactivation parameters used to denature complement proteins in serum without destroying immunoglobulins.

Air-Displacement Pipette

Type A pipette with an air cushion between internal piston and sample; ideal for standard aqueous solutions.

Positive-Displacement Pipette

Type D pipette where internal plunger directly contacts fluid without an air cushion; mandatory for viscous, volatile, or infectious fluids.

Forward Pipetting

Standard technique pressing plunger to 1st stop to aspirate and 2nd stop to dispense; best for thin aqueous liquids.

Reverse Pipetting

Technique pressing plunger to 2nd stop to aspirate and 1st stop to dispense; leaves a sacrificial excess volume to prevent boundary layer loss in viscous fluids.

Pre-wetting

Aspirating and dispensing liquid 2 to 3 times prior to transfer to humidify dead air space and prevent up to 2% volume deficit.

90 Degrees Vertical

Required aspiration angle for air-displacement pipetting to maintain hydrostatic balance and prevent up to 1.5% over-aspiration.

20 to 45 Degrees

Recommended dispensing angle against the inner vessel wall to utilize surface tension and prevent droplet retention.

Boundary Layer

Sticky liquid film adhering to inner plastic tip walls during transfers of viscous protein-rich fluids like serum or glycerol.

Hand Warmth Factor

Thermal expansion of internal air cushion caused by continuous holding of pipette handle, resulting in systematic under-delivery.

Spring Decompression

Post-analytical pipette maintenance step of dialing volume selector to maximum setting before vertical storage to relieve internal spring tension.

P100 Pipette

Mechanical micropipette optimized for volume transfers between 10 µL and 100 µL using yellow tips.

P200 Pipette

Mechanical micropipette optimized for volume transfers between 20 µL and 200 µL using yellow tips.

P1000 Pipette

Mechanical micropipette optimized for volume transfers between 100 µL and 1000 µL using blue tips.

Yellow Pipette Tip

Standard disposable tip size designed to fit P100 and P200 pipette shaft cones.

Blue Pipette Tip

Standard disposable tip size designed to fit P1000 pipette shaft cones.

Plunger First Stop

Tactile resistance point on a mechanical pipette plunger used to measure and calibrate exact nominal volume.

Plunger Second Stop

Final compression point on a mechanical pipette plunger used for blowout to expel residual fluid droplets during forward pipetting.

Tip Ejector Knob

Button pressed to release used pipette tips directly into biohazard containment without manual touch.

Microhematocrit Capillary Tube

Plain glass tube measuring 75 mm in length and 75 µL capacity used for capillary metrology verification of pipetting accuracy.

1.0 mm Column Height

Equivalent physical length corresponding to exactly 1.0 µL of fluid volume inside a standard microhematocrit capillary tube.

Percent Recovery

Metrological calculation evaluated as (Measured Capillary Column Height divided by Target Volume) multiplied by 100.

ISO 8655-2

International quality standard governing volumetric specs, tolerances, and operational testing of piston-operated pipettes.

Blowout Pipette

Serological pipette marked with etched rings at the top requiring final drop to be forced out by air bulb (labeled TC).

Solute

Substance being dissolved or diluted in a liquid mixture, such as patient serum or stock standard.

Diluent

Solvent liquid added to a concentrate to reduce its concentration, typically saline or distilled water.

Total Volume

Combined volume of solute plus diluent in a final diluted mixture.

Simple Dilution

Single-step reduction in concentration formed by mixing a set volume of solute into a fixed volume of diluent.

Compound Dilution

Multi-step dilution sequence where the diluted product of one step serves as the starting stock for the next step.

Serial Dilution

Specialized compound dilution maintaining a constant dilution fold across progressive steps, creating geometric concentration decline.

Dilution Fold

Constant factor N by which concentration decreases at each step in serial dilution; calculated as Total Volume divided by Transferred Volume.

Antibody Titer

Reciprocal of the highest serum dilution demonstrating a positive visible reaction; reported as a single whole number.

C1V1 = C2V2

Volumetric equation used to calculate required stock reagent volumes and diluents when scaling concentrated solutions.

Analytical Measurement Range

Range of analyte concentrations a clinical analyzer can directly and accurately measure without sample dilution.

Prozone Phenomenon

False-negative reaction caused by extreme antibody excess saturating antigen sites and preventing macroscopic cross-linking.

Postzone Phenomenon

False-negative reaction caused by antigen excess overwhelming available antibody binding sites.

Zone of Equivalence

Ideal ratio of antigen to antibody allowing optimal lattice formation and visible agglutination/precipitation.

Standard Curve

Plot of absorbance versus concentration generated by serially diluting a known calibrator, used to quantify patient analytes.

1:10 Dilution

Dilution comprising 1 part solute and 9 parts diluent, yielding a total volume of 10 parts (1 in 10).

1:10 Ratio

Mixing ratio comprising 1 part solute and 10 parts diluent, yielding a total volume of 11 parts (1 to 10).

Hemagglutination

Macroscopic aggregation of red blood cells caused by cross-linking antigen-specific antibodies.

AMR Overflow

Analyzer error flag indicating patient specimen concentration exceeds upper linear limit of detection, requiring compound dilution.

2-Fold Serial Dilution

Serial dilution progression where concentration halves at each step (e.g., 1:2, 1:4, 1:8, 1:16).

Hazard

Object, chemical, or situation with inherent potential to cause adverse effects or harm to human health or property.

Risk

Combination of the probability of an incident occurring and the severity of harm resulting from it.

PASS Method

Fire extinguisher operation sequence: Pull pin, Aim at base, Squeeze handle, Sweep side to side.

RACE Method

Fire emergency action plan: Rescue persons in danger, Alarm, Contain fire doors, Extinguish or evacuate.

Safety Data Sheet

Standardized 16-section document providing detailed chemical hazard, handling, storage, and emergency information.

NFPA 704

Diamond hazard rating system coding health (blue), flammability (red), instability (yellow), and special hazards (white) from 0 to 4.

Post-Exposure Prophylaxis

Antiretroviral regimen initiated within 72 hours of HIV exposure, followed by testing at 6 weeks, 12 weeks, and 6 months.

1:10 Bleach Solution

10% sodium hypochlorite solution prepared fresh daily for worksurface decontamination against bloodborne pathogens.

Universal Biohazard Symbol

Specific three-crescent symbol required on fluorescent orange or red leak-proof biohazard waste containers.

BSL-1

Biosafety level suited for well-characterized agents not known to consistently cause disease in immunocompetent adults.

BSL-2

Biosafety level required for moderate-risk bloodborne pathogens like HIV, Hepatitis B Virus, and Staphylococcus aureus.

BSL-3

Biosafety level required for indigenous or exotic agents transmitted via aerosols causing serious or lethal infections (e.g., TB).

BSL-4

Biosafety level required for dangerous, exotic agents posing high risk of life-threatening aerosol infections (e.g., Ebola).

Category B Infectious Substance

Biological material transported under UN 3373 guidelines using certified triple packaging systems.

Triple Packaging System

Shipping containment consisting of primary leakproof receptacle, secondary leakproof packaging with absorbent material, and rigid outer box.

Sharps Container

Puncture-resistant, rigid, leak-proof container marked with biohazard symbol for disposing needles, lancets, and snapped capillary glass.

OSHA BBP Standard

Federal regulation 29 CFR 1910.1030 protecting healthcare workers from occupational exposure to bloodborne pathogens.

Diagnostic Sensitivity

Probability that a test result will be positive in the presence of disease; calculated as TP / (TP + FN) x 100.

Diagnostic Specificity

Probability that a test result will be negative in the absence of disease; calculated as TN / (TN + FP) x 100.

Positive Predictive Value

Probability that a patient with a positive test result truly has the disease; calculated as TP / (TP + FP) x 100.

Negative Predictive Value

Probability that a patient with a negative test result is truly disease-free; calculated as TN / (TN + FN) x 100.

Mean

Arithmetic average of a set of quality control data values, representing central tendency.

Standard Deviation

Statistical metric quantifying the dispersion or spread of values around the mean in a control dataset.

Coefficient of Variation

Standard deviation expressed as a percentage of the mean (%CV = SD/Mean x 100); measures analytical precision.

Levey-Jennings Chart

Control chart plotting daily quality control values against mean and standard deviation control limits (±1, ±2, ±3 SD).

Trend

Gradual, progressive drift of QC values in one direction over 6 or more consecutive runs, indicating reagent or instrument degradation.

Shift

Abrupt, sudden change in QC control values that establishes a new continuous baseline on one side of the mean.

Lean 6S

Quality workplace optimization methodology focusing on waste elimination through Sort, Straighten, Scrub, Safety, Standardize, and Sustain.

Six Sigma DMAIC

Data-driven quality improvement framework targeting

Root Cause Analysis

Structured problem-solving process identifying underlying systemic causes of nonconforming laboratory events or errors.

Delta Check

Quality review step comparing a current patient result against previous historical test results to detect misidentification or errors.

CLIA '88

Federal regulation categorizing clinical diagnostic tests into waived, provider-performed microscopy, and nonwaived (moderate/high) complexity.

CLSI

Nonprofit organization issuing consensus-based guidelines considered the standard of care for clinical laboratory procedures.

CAP

Voluntary accrediting agency performing peer-led inspections and providing proficiency testing surveys to clinical laboratories.

EDTA

Anticoagulant that chelates calcium and metal ions; ideal for molecular testing but inhibits metal-dependent enzyme immunoassays.

Sodium Azide

Common chemical preservative in serological reagents that can interfere with enzymatic assays and requires SDS tracking.

Capillary Action

Spontaneous movement of liquid up a narrow glass tube driven by surface tension and adhesion.

Volumetric Pipette

Pipette calibrated to deliver (TD) a single fixed volume of liquid with high accuracy, leaving a small drop behind in tip.