Phlebotomy Abbreviations: The Complete List You Need to Know

Phlebotomy requisitions, lab orders, chain-of-custody forms, and NHA CPT and ASCP PBT exam questions all assume you know the abbreviations cold. This is a complete reference covering every tube, test, procedure, safety, and regulatory abbreviation you'll encounter in training, on the exam, and on the job.

How Abbreviations Are Tested on the Certification Exam

The exam doesn't ask you to define SST in isolation. It puts the abbreviation in a scenario: "A physician orders a CMP and CBC STAT. What tubes do you collect and in what order?" You need to know CMP runs on serum (gold SST), CBC runs on EDTA (lavender), what STAT means, and the correct order of draw, all from a single question stem. This reference organizes abbreviations so you can learn them alongside their clinical context, not just as a list to memorize.

Tube and Collection System Abbreviations

Abbreviation	Full Name	Clinical Context
ETS	Evacuated Tube System	BD Vacutainer and equivalent closed-system collection. The vacuum in each tube draws a predetermined blood volume.
SST	Serum Separator Tube	Gold/tiger top with clot activator and thixotropic gel. Produces serum after centrifugation. Most common tube in outpatient chemistry labs.
PST	Plasma Separator Tube	Mint green with lithium heparin and gel. Produces plasma. Faster results than SST because no clot time required.
EDTA	Ethylenediaminetetraacetic acid	Anticoagulant in lavender and pink tubes. Permanently chelates calcium to prevent clotting. K2 EDTA is the current standard form.
SPS	Sodium Polyanethol Sulfonate	Yellow blood culture tube additive. Neutralizes antibiotics, inhibits complement and phagocytosis to preserve organisms for culture.
ACD	Acid Citrate Dextrose	Yellow top (different from SPS). Used for HLA typing, paternity testing, DNA studies. Rarely used in routine collection.
NaF	Sodium Fluoride	Glycolytic inhibitor in gray tubes. Blocks enolase to prevent glucose metabolism. Preserves glucose for up to 24 hours.
KOx	Potassium Oxalate	Secondary anticoagulant in gray tubes. Pairs with NaF. Chelates calcium to prevent clotting.
Na Citrate	Sodium Citrate	Anticoagulant in light blue (3.2%) and black (3.8%) tubes. Reversibly chelates calcium. Light blue = coagulation; black = Westergren ESR only.
Li Hep	Lithium Heparin	Anticoagulant in green tubes. Inhibits thrombin and factor Xa. Cannot be used for coagulation testing or lithium drug levels.

Hematology Test Abbreviations

Abbreviation	Full Name	Tube / Notes
CBC	Complete Blood Count	Lavender (EDTA). Includes WBC, RBC, Hgb, Hct, MCV, MCH, MCHC, RDW, platelet count.
WBC	White Blood Cell count	Total leukocyte count. Elevated in infection, inflammation, leukemia. Part of CBC.
RBC	Red Blood Cell count	Total erythrocyte count. Part of CBC.
Hgb / Hb	Hemoglobin	Oxygen-carrying protein in RBCs. Decreased in anemia and blood loss.
Hct / PCV	Hematocrit / Packed Cell Volume	Percentage of blood volume occupied by RBCs. Roughly 3x the hemoglobin value.
H&H	Hemoglobin and Hematocrit	Common combined order. Both drawn in lavender tube as part of CBC.
MCV	Mean Corpuscular Volume	Average RBC size. Low = microcytic (iron deficiency). High = macrocytic (B12/folate deficiency).
MCH	Mean Corpuscular Hemoglobin	Average hemoglobin content per RBC. Part of CBC indices.
MCHC	Mean Corpuscular Hemoglobin Concentration	Average hemoglobin concentration relative to cell volume. Decreased in iron deficiency anemia.
RDW	Red Cell Distribution Width	Variation in RBC size. Elevated RDW suggests mixed deficiency (iron + B12, for example).
Plt	Platelet count	Thrombocytes. Part of CBC. Low = thrombocytopenia.
MPV	Mean Platelet Volume	Average platelet size. Large platelets suggest increased platelet production (as in ITP).
Diff	Differential	WBC differential count: percentage of each leukocyte type (neutrophils, lymphocytes, monocytes, eosinophils, basophils).
Segs / Polys / PMN	Segmented neutrophils / Polymorphonuclear cells	Mature neutrophils. 50-70% of WBC differential. First responders to bacterial infection.
Bands	Band neutrophils	Immature neutrophils. Elevated bands ("left shift") indicates acute infection or stress on bone marrow.
Lymphs	Lymphocytes	20-40% of WBC differential. B and T cells. Elevated in viral infections and some leukemias.
Monos	Monocytes	2-8% of WBC. Largest leukocyte. Mature into macrophages in tissues.
Eos	Eosinophils	1-4% of WBC. Elevated in allergic conditions and parasitic infections.
Basos	Basophils	0-1% of WBC. Least common. Release histamine in allergic and inflammatory reactions.
ESR	Erythrocyte Sedimentation Rate	Black tube (3.8% sodium citrate, Westergren method). Non-specific inflammatory marker. Rate RBCs settle in 1 hour.
Retic	Reticulocyte count	Lavender tube. Immature RBCs. Elevated in hemolysis or blood loss (bone marrow is producing more RBCs).
HbA1c / A1C	Glycosylated hemoglobin	Lavender tube. Reflects average blood glucose over 2-3 months. Diabetes threshold: 6.5%.

Chemistry and Metabolic Panel Abbreviations

Abbreviation	Full Name	Tube / Notes
BMP	Basic Metabolic Panel	Gold SST or green. Sodium, potassium, chloride, CO2, BUN, creatinine, glucose, calcium.
CMP	Comprehensive Metabolic Panel	Gold SST. BMP + total protein, albumin, bilirubin, ALP, AST, ALT.
BUN	Blood Urea Nitrogen	Waste product from protein metabolism. Elevated in kidney disease and dehydration.
Cr / Creat	Creatinine	Muscle metabolism waste. More reliable kidney marker than BUN. Stable regardless of diet.
Na	Sodium	Primary extracellular cation. Hyponatremia and hypernatremia both have neurological consequences.
K	Potassium	Primary intracellular cation. EDTA carryover and hemolysis both falsely elevate potassium. Critical cardiac arrhythmia risk at extremes.
Cl	Chloride	Primary extracellular anion. Part of electrolyte panel.
CO2 / HCO3	Bicarbonate / Carbon Dioxide	Acid-base balance marker on electrolyte panels. Not the same as PCO2 from an ABG.
Ca	Calcium (total)	Falsely lowered by EDTA or citrate contamination. Critical for cardiac and neuromuscular function.
Mg	Magnesium	Also affected by EDTA carryover. Important for cardiac rhythm and muscle function.
Phos	Phosphorus / Phosphate	Falsely elevated by hemolysis (released from RBCs). Important in kidney disease and electrolyte balance.
Gluc / FBG / FBS	Glucose / Fasting Blood Glucose / Fasting Blood Sugar	Gray tube for accuracy. Without fluoride, glucose drops 5-7 mg/dL per hour at room temperature. Diabetes threshold: fasting 126 mg/dL or higher on two occasions.
GTT / OGTT	Glucose Tolerance Test / Oral Glucose Tolerance Test	Gray tubes at timed intervals after glucose challenge. Used to diagnose gestational diabetes and Type 2 DM.
LFTs	Liver Function Tests	Gold SST. Includes AST, ALT, ALP, GGT, total bilirubin, direct bilirubin, albumin, total protein.
AST	Aspartate Aminotransferase	Liver enzyme. Also elevated in muscle injury. Falsely elevated by hemolysis (high concentration in RBCs).
ALT	Alanine Aminotransferase	More liver-specific than AST. Primary marker for hepatocellular damage.
ALP	Alkaline Phosphatase	Elevated in liver disease and bone disorders. Also elevated physiologically in growing adolescents and pregnancy.
GGT	Gamma-Glutamyl Transferase	Sensitive marker for liver disease, especially alcohol-related. Elevated in biliary obstruction.
T. Bili / D. Bili	Total Bilirubin / Direct Bilirubin	Protect from light during transport. Falsely decreased by light exposure. Elevated in liver disease and hemolysis.
Alb	Albumin	Major plasma protein. Decreased in malnutrition, liver disease, kidney disease (nephrotic syndrome).
LDH	Lactate Dehydrogenase	Non-specific tissue injury marker. Falsely elevated by hemolysis. Present in high concentration in RBCs.
TSH	Thyroid Stimulating Hormone	Gold SST. Primary thyroid screening test. Elevated = hypothyroidism. Decreased = hyperthyroidism.
T3 / T4 / FT4	Triiodothyronine / Thyroxine / Free T4	Gold SST. Thyroid hormones. Used with TSH for complete thyroid evaluation.
HDL / LDL	High-Density Lipoprotein / Low-Density Lipoprotein	Gold SST. Lipid panel. Higher HDL is protective. Higher LDL increases cardiovascular risk.
TG / Trig	Triglycerides	Fasting specimen required for accurate triglyceride measurement. Part of standard lipid panel.
CRP / hsCRP	C-Reactive Protein / High-Sensitivity CRP	Gold SST. Non-specific inflammatory marker. hsCRP is used for cardiac risk stratification at low concentrations.
UA	Urinalysis	Urine specimen. Random or clean-catch midstream. Chemical dipstick + microscopic if indicated.
C&S	Culture and Sensitivity	Microbiological culture to identify organism + sensitivity testing to guide antibiotic selection.

Cardiac Biomarker Abbreviations

Abbreviation	Full Name	Clinical Context
Trop I / Trop T	Troponin I / Troponin T	Gold SST. Current standard for MI diagnosis. Rises 3-6 hours post-MI, peaks at 12-24 hours, elevated for days. Most sensitive and specific cardiac marker available.
CK-MB	Creatine Kinase MB isoenzyme	Gold SST. Peaks at 12-24 hours, returns to baseline within 24-48 hours (earlier normalization than troponin makes it useful for reinfarction detection when troponin remains elevated). Used for reinfarction detection when troponin stays elevated from initial MI. Not as specific as troponin.
CK / CPK	Creatine Kinase / Creatine Phosphokinase	Elevated in muscle injury, rhabdomyolysis, and MI. Total CK is not cardiac-specific; CK-MB isoenzyme is.
BNP / NT-proBNP	B-type Natriuretic Peptide / N-terminal proBNP	EDTA tube (lavender) for BNP, gold SST for NT-proBNP. Elevated in heart failure. Used to differentiate cardiac from pulmonary causes of dyspnea.
D-dimer	D-dimer fibrin degradation product	Light blue (citrate) tube. Elevated in DVT, PE, DIC. Normal D-dimer is useful to rule out clot when pre-test probability is low.

Coagulation Test Abbreviations

Abbreviation	Full Name	Clinical Context
PT	Prothrombin Time	Light blue (3.2% sodium citrate). Measures extrinsic clotting pathway. Elevated in warfarin therapy, liver disease, vitamin K deficiency.
INR	International Normalized Ratio	Standardized PT result. Therapeutic warfarin range is typically 2.0-3.0. Allows comparison across different laboratory reagents.
PTT / aPTT	Partial Thromboplastin Time / Activated PTT	Light blue tube. Measures intrinsic clotting pathway. Used to monitor unfractionated heparin therapy. Elevated in hemophilia A and B.
Fibrinogen	Fibrinogen (Factor I)	Light blue tube. Decreased in DIC, liver failure. Consumed in massive clot formation.
DIC	Disseminated Intravascular Coagulation	Pathological activation of both clotting and fibrinolysis simultaneously. Associated with elevated D-dimer, elevated PT/PTT, decreased fibrinogen and platelets.
DVT	Deep Vein Thrombosis	Blood clot in deep vein, usually leg. Risk of pulmonary embolism. D-dimer used in workup.
PE	Pulmonary Embolism	Blood clot in pulmonary vasculature. D-dimer elevated but non-specific. CT angiography confirms.

Special Collections and ABG Abbreviations

Abbreviation	Full Name	Context
ABG	Arterial Blood Gas	Arterial collection (usually radial artery). Measures pH, PO2, PCO2, HCO3, O2 saturation. Transport on ice. Allen's test required first.
pH	Potential of Hydrogen	ABG. Acid-base balance. Normal 7.35-7.45. Below 7.35 = acidosis. Above 7.45 = alkalosis.
PO2 / PCO2	Partial pressure of oxygen / carbon dioxide	ABG. PO2 measures oxygenation. PCO2 reflects ventilation. Transport on ice immediately.
SpO2	Peripheral oxygen saturation (pulse oximetry)	Non-invasive. Measures hemoglobin oxygen saturation via light sensor. Not the same as PO2 from ABG.
BC / BCx	Blood Culture	Yellow SPS tube or directly inoculated aerobic/anaerobic bottles. Collected first, before all other tubes.
BAC	Blood Alcohol Concentration	Gray tube. Non-alcohol antiseptic (chlorhexidine or povidone-iodine) required. Alcohol swab invalidates forensic specimens.
TDM	Therapeutic Drug Monitoring	Gold SST. Timing is critical. Trough = just before next dose. Peak = collected at specific post-dose interval.
Trough	Trough level	Minimum drug concentration. Collected immediately before the next scheduled dose.
Peak	Peak level	Maximum drug concentration. Collected at a drug-specific interval after dose administration.
POC	Point of Care	Testing performed at or near the patient (bedside, ER, clinic) rather than the central lab. Faster results, less precision than automated analyzers.

Pre-Analytical and Quality Control Abbreviations

Abbreviation	Full Name	Context
QNS	Quantity Not Sufficient	Specimen rejected because volume is inadequate to run the ordered tests. Requires recollection.
H	Hemolysis	RBC rupture releasing intracellular contents into plasma/serum. Pink or red discoloration. Falsely elevates K, LDH, AST, phosphorus.
L	Lipemia	Milky or turbid plasma from elevated triglycerides. Can interfere with spectrophotometric assays.
I	Icterus	Yellow plasma from elevated bilirubin. Can interfere with colorimetric assays. Specimen must be protected from light.
HLI Index	Hemolysis, Lipemia, Icterus Index	Automated assessment of specimen quality. Flags specimens where any of the three conditions may interfere with results.
TAT	Turnaround Time	Time from specimen collection to reported result. STAT and routine specimens have different TAT expectations.
QC	Quality Control	Process of testing known control materials to verify instrument accuracy. Required before patient testing begins.
QA	Quality Assurance	Broader program to ensure overall laboratory quality, including pre-analytical, analytical, and post-analytical phases.
SOP	Standard Operating Procedure	Written, step-by-step procedural instructions. Required by CLIA for all laboratory procedures.

Anatomical and Procedural Abbreviations

Abbreviation	Full Name	Context
AC	Antecubital	The inside of the elbow. Primary venipuncture site. Median cubital, cephalic, and basilic veins are all here.
IV	Intravenous	Into a vein. Never collect from an IV site unless it's the absolute last resort (2-minute pause + 2 discard tubes required).
PICC	Peripherally Inserted Central Catheter	Long-term IV access inserted in arm, tip in superior vena cava. Phlebotomists don't routinely collect from PICCs without specific training.
CVL / CVC	Central Venous Line / Central Venous Catheter	Central access device. Collection from CVLs is a specialized nursing/medical procedure, not routine phlebotomy.
NPO	Nil per os (Nothing by mouth)	Patient is fasting. Required for fasting glucose, lipid panel, and many surgical procedures.
STAT	Statim (Latin: immediately)	Urgent specimen collection and processing required. STAT specimens go to the front of the processing queue.
DOB	Date of Birth	Required patient identifier. Along with full name, must be confirmed before every draw. Room number and bed number are never acceptable as patient identifiers.
MRN	Medical Record Number	Acceptable second patient identifier along with date of birth when confirming patient identity.
R/O	Rule out	Clinical shorthand on requisitions. "R/O MI" means tests ordered to exclude myocardial infarction from the diagnosis.

Safety and Regulatory Abbreviations

Abbreviation	Full Name	Exam Relevance
OSHA	Occupational Safety and Health Administration	Enforces Bloodborne Pathogens Standard (29 CFR 1910.1030). Requires HBV vaccine, exposure control plan, and post-exposure follow-up at no cost to employee.
BBP	Bloodborne Pathogens	HIV, HBV, HCV are the primary three. HBV has the highest transmission risk from needlestick. OSHA BBP Standard governs all healthcare worker protections.
PPE	Personal Protective Equipment	Gloves required for every venipuncture. Gown, mask, and eye protection for splash risk. Employer required to provide and maintain.
HBV / HCV / HIV	Hepatitis B / Hepatitis C / Human Immunodeficiency Virus	Primary bloodborne pathogens. HBV: highest needlestick risk (up to 30%). HCV: intermediate (1-3%). HIV: low (0.3%). PEP for HIV must begin within 72 hours of exposure.
SDS	Safety Data Sheet	Replaced MSDS. Contains hazard information for chemical substances. Must be accessible to all employees in the work area.
CLIA	Clinical Laboratory Improvement Amendments	Federal regulations governing all human specimen testing in the US. Established standards for laboratory quality, personnel, and proficiency testing.
CLSI	Clinical and Laboratory Standards Institute	Publishes voluntary consensus standards including GP41 (order of draw, venipuncture), GP42 (skin puncture), and others. Both certification exams reference CLSI standards directly.
CAP	College of American Pathologists	Laboratory accreditation organization. More rigorous than CLIA minimum standards.
TJC	The Joint Commission	Accredits hospitals and healthcare organizations. Sets patient identification and safety standards that phlebotomists must follow.
HIPAA	Health Insurance Portability and Accountability Act	Federal law protecting patient health information (PHI). Phlebotomists cannot disclose test results or patient information to unauthorized individuals.
PHI	Protected Health Information	Any individually identifiable health information. Name, DOB, diagnosis, test results, and room number all qualify as PHI.

Certification Abbreviations

Abbreviation	Full Name	Notes
ASCP	American Society for Clinical Pathology	The most widely recognized phlebotomy certification body in the US. Board of Certification (BOC) administers the PBT exam.
PBT	Phlebotomy Technician (ASCP credential)	ASCP PBT certification requires clinical training hours and passing the BOC exam. Renewal requires continuing education credits.
NHA	National Healthcareer Association	Issues CPT (Certified Phlebotomy Technician) credential. Accepted in many states and facilities.
CPT	Certified Phlebotomy Technician	NHA credential. Different from the medical billing CPT code abbreviation.
AMT	American Medical Technologists	Issues RPT (Registered Phlebotomy Technician) credential.
CE	Continuing Education	Required for ASCP PBT certification renewal. Specific credit requirements set by ASCP BOC.
NAACLS	National Accrediting Agency for Clinical Laboratory Sciences	Accredits phlebotomy training programs. Graduates of NAACLS-accredited programs meet the educational requirement for ASCP PBT certification.

Commonly Confused Abbreviations

These pairs appear on the certification exam specifically because they're easy to mix up:

PT vs. PTT: PT = prothrombin time (extrinsic pathway, warfarin monitoring). PTT = partial thromboplastin time (intrinsic pathway, heparin monitoring). Both use the light blue tube. The difference is the clinical question and which pathway is being tested.
INR vs. PTT: INR is a standardized version of the PT result. PTT is a different test entirely. Warfarin is monitored by INR. Unfractionated heparin is monitored by PTT.
BMP vs. CMP: BMP (Basic) has 8 components. CMP (Comprehensive) adds liver panel tests. Both run on gold SST.
ABG vs. SpO2: ABG is arterial blood collected at the wrist. SpO2 is a non-invasive pulse oximetry reading. ABG measures actual oxygen and CO2 partial pressures plus pH. SpO2 measures hemoglobin saturation only.
ESR tube vs. coagulation tube: ESR uses black tube (3.8% citrate). Coagulation uses light blue tube (3.2% citrate). Not interchangeable.
SPS vs. ACD: Both yellow tubes. SPS = blood cultures. ACD = HLA typing and DNA studies. Read the label.

Frequently Asked Questions

What does STAT mean in phlebotomy?

STAT comes from the Latin statim, meaning immediately. A STAT order requires urgent specimen collection and prioritized processing. STAT specimens typically have turnaround time requirements of 30-60 minutes depending on the facility and test.

What does QNS mean on a lab result?

QNS stands for Quantity Not Sufficient. The lab is indicating that the specimen volume collected was inadequate to run the ordered tests. A redraw is required. Common causes include premature needle withdrawal, difficult stick with slow fill, or requesting too many tests on a single tube.

What is the HLI index?

The HLI index stands for Hemolysis, Lipemia, and Icterus. Automated analyzers assess each specimen for these three conditions on a numeric scale. A high H index (hemolysis) suggests the specimen was improperly collected or processed. A high L index (lipemia) usually reflects the patient's clinical state. A high I index (icterus) reflects elevated bilirubin.

What does NPO mean and why does it matter for phlebotomy?

NPO means "nil per os," Latin for nothing by mouth. A patient who is NPO has been fasting. This is relevant because fasting status affects glucose (fasting required for accurate fasting glucose), lipid panel (fasting required for triglycerides and LDL calculation), and some other tests. Confirm fasting status before collecting glucose tolerance test specimens.

What does the CLSI govern in phlebotomy?

CLSI (Clinical and Laboratory Standards Institute) publishes the consensus standards that govern phlebotomy practice. The most relevant for phlebotomists is GP41 (Collection of Diagnostic Venous Blood Specimens), which defines the order of draw, needle gauge recommendations, tourniquet time limits, and tube inversion requirements.