Pre-Analytical Sources and Errors in Specimen Handling & Special Blood Collection Procedures

Vocabulary practice flashcards covering pre-analytical variables, specimen processing, and specialized phlebotomy collection procedures.

Pre-analytical Phase

The laboratory testing phase encompassing specimen collection, handling, transport, and processing prior to analysis, which accounts for approximately $56\%$ of all laboratory errors.

Analytic Phase

The phase of the laboratory process during which the actual testing and chemical or microscopic analysis of the specimen occurs.

Post-analytic Phase

The final stage of laboratory workflow that involves reporting results to healthcare providers and handling follow-up or repeat testing.

Aliquot

A portion of a well-mixed specimen taken for chemical analysis and transferred from the primary collection tube to a secondary tube.

Fasting Blood Sugar (FBS)

A blood test measuring glucose levels after refraining from food intake, with an expected normal range of $60\text{--}100\,\text{mg/dL}$.

Two-Hour Postprandial Glucose Test

A test used to screen for diabetes and gestational diabetes and to evaluate insulin therapy, requiring blood collection $2\,\text{hours}$ after a meal (normal non-diabetic value is $< 140\,\text{mg/dL}$; diabetic target is $< 180\,\text{mg/dL}$).

Glucose Tolerance Test (GTT)

A diagnostic procedure used to diagnose diabetes mellitus and hypoglycemia, requiring an initial fasting sample, ingestion of a $75\,\text{g}$ glucose solution within $5\,\text{minutes}$, and timed blood collections.

Lactose Tolerance Test

A procedure conducted similarly to a glucose tolerance test that evaluates a patient's ability to digest milk sugars by administering lactose rather than glucose.

Therapeutic Drug Monitoring (TDM)

The periodic collection and testing of blood samples to measure specific drug concentrations, preventing under-dosing or drug toxicity.

Peak Level

The highest concentration of a drug in a patient's bloodstream, drawn $30\,\text{minutes}$ after IV administration, $60\,\text{minutes}$ after intramuscular injection, or $1\text{--}2\,\text{hours}$ after oral intake.

Trough Level

The lowest concentration of a therapeutic drug in blood circulation, drawn precisely $30\,\text{minutes}$ before administering the next scheduled dose.

Therapeutic Phlebotomy

The clinical withdrawal of a large unit of whole blood as a treatment modality for medical conditions such as polycythemia.

Polycythemia

A condition characterized by an abnormally high red blood cell count and elevated hematocrit level, resulting in hyperviscous blood.

Human Chorionic Gonadotropin (hCG)

A hormone produced by developing placental cells that appears $8\text{--}10\,\text{days}$ after conception and reaches peak concentration in first-morning urine specimens.

Cerebrospinal Fluid (CSF)

A liquid that surrounds and cushions the brain and spinal cord, collected by a physician through a lumbar puncture (spinal tap) and requiring immediate, sterile transport.

Sputum Specimen

Mucus or phlegm expelled from the lower respiratory tract via deep coughing, ideally collected as a first-morning specimen to evaluate for tuberculosis (Mycobacterium tuberculosis).

Sweat Chloride Test

A diagnostic procedure measuring the salt content of perspiration to identify cystic fibrosis, where a result of $\ge 60\,\text{mmol/L}$ confirms presence of the disease.

Buccal Swab

A collection swab taken from the inside of the cheek to collect epithelial cells, commonly utilized for DNA analysis.

Urea Breath Test

A non-invasive diagnostic test evaluating exhaled breath to detect active infection by the bacterium Helicobacter pylori (H. pylori).

Autologous Donation

The donation of a patient's own blood prior to an elective surgical procedure for future personal transfusion.

Chain of Custody

A detailed, unbroken legal tracking document accounting for the identification, collection, handling, transfer, and analysis of forensic specimens.

Urine Drug Screen Integrity Criteria

Standard specimen criteria requiring at least $45\,\text{mL}$ of urine, a temperature of approximately $37^\circ\text{C}$, and a specific gravity between $1.003$ and $1.025$ to prevent adulteration or recollection.