Lab Test Primer

Clinical Laboratory

Hematology: Examination of cellular elements of blood (peripheral smear); includes separately clotting factors
Clinical chemistry: Measurement of >200 substances in serum and body fluids
Transfusion medicine/blood banking: Blood donor screening/testing, blood components, compatibility testing
Microbiology/immunology: Microbial identification, susceptibility testing, determinations of immunity (AKA the reason why we’re drowning in cytokines and bacteria right now)
Immunoassays: Endocrine testing, toxicology, and therapeutic drug monitoring
Medical microscopy/urinalysis: Examination of body fluids (using micro-/macroscopic and physiochemical methods)

Analytical Variables

Pre-analytical variables: Patient preparation, specimen collection/handling
Analytical variables: During/related to testing process (manual vs. automated); factors related to instrumentation (precision, accuracy)
Post-analytical: Result reporting (calculations, transcription)

Test Results and Values

Reference range: a range of values/results considered to be “normal” for a certain type of quantity. This will tend to differ based on the stated description of a group of people that shares certain characteristics.
Panic/critical values: threshold values beyond the expected range; can be life-threatening
Delta check: a lab quality control measure that compares successive samples from the same patient

Laboratory

Include separate tests that are related to the same organ system or are commonly ordered together.

Electrolyte panel: tests for Na+, K+, Cl - , CO2 levels
Lipid panel: cholesterol (HDL/LDL/other), triglycerides
Basic metabolic panel: Na+, KCl, Cl - , CO2, creatinine, BUN, glucose, Ca2+
Hepatic function panel: albumin, alkaline phosphatase, ALT, AST, total bilirubin, direct bilirubin, total protein
Obstetrical panel: ABO and Rh blood typing, antibody screen, syphilis IgG, rubella Ab, CBC, HIV, hepatitis B surface antigen

Hematology

For more on hematology, see here: Hematology

Complete Blood Count (CBC)

Hemoglobin
Hematocrit
White blood cell (WBC) count
Platelet count

Troponin

Troponin is a regulatory complex that modulates muscle contraction. Troponin I is the most specific marker for acute myocardial infarction (MI) and is considered the gold standard.

Detectable within 4-6 hours with a peak at 12-18 hours. Levels will return to baseline at 6 days, making timing key in detection of acute MI.