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Clinical & Prescription Reference Dictionary

Medical & Prescription Abbreviations

Decipher prescription instructions (b.i.d., p.o., PRN), laboratory diagnostic panels (CBC, HbA1c, eGFR), clinical acronyms (COPD, GERD, STEMI), and vital sign indicators.

All CategoriesPrescription & DosageDiagnostic & Lab TestsDiseases & Clinical ConditionsVital Signs & AnatomyAgencies & Regulatory
Prescription & Dosage

b.i.d. (BID)

Bis in die (Twice a day)

Instructs the patient to take the dose twice daily, usually approximately 12 hours apart.

Prescription & Dosage

t.i.d. (TID)

Ter in die (Three times a day)

Take the medication three times during waking hours, typically every 8 hours.

Prescription & Dosage

q.i.d. (QID)

Quater in die (Four times a day)

Take the medication four times daily, typically every 6 hours.

Prescription & Dosage

q.d. (QD)

Quaque die (Every day / Once daily)

Take once each day at approximately the same time.

Prescription & Dosage

p.o. (PO)

Per os (By mouth / Orally)

Indicates oral administration (swallowing tablets, capsules, or liquids).

Prescription & Dosage

PRN

Pro re nata (As needed / When necessary)

Take only when symptoms arise (e.g., for pain, nausea, fever) within specified maximum limits.

Prescription & Dosage

stat

Statim (Immediately / At once)

Indicates an urgent single dose required without delay.

Prescription & Dosage

a.c.

Ante cibum (Before meals)

Take medication 30–60 minutes before eating.

Prescription & Dosage

p.c.

Post cibum (After meals)

Take medication following a meal to reduce gastrointestinal irritation.

Prescription & Dosage

q.h.s. / h.s.

Hora somni (At bedtime)

Take the medication in the evening right before sleep.

Prescription & Dosage

NPO

Nil per os (Nothing by mouth)

Strict medical instruction withholding all food, fluids, and oral medications (common before surgery).

Prescription & Dosage

gtt

Guttae (Drops)

Used for eye, ear, or nasal drop prescriptions.

Prescription & Dosage

IV

Intravenous

Medication or fluids administered directly into a vein.

Prescription & Dosage

IM

Intramuscular

Injected into muscle tissue (common for vaccines like Tdap, Hepatitis B).

Prescription & Dosage

SC / SubQ

Subcutaneous

Injected into the fatty tissue just beneath the skin (e.g., Insulin, Low-molecular-weight heparin).

Diagnostic & Lab Tests

CBC

Complete Blood Count

Measures red blood cells, white blood cells, hemoglobin, hematocrit, and platelets to evaluate infection or anemia.

Diagnostic & Lab Tests

HbA1c

Glycated Hemoglobin

Reflects average blood glucose control over the past 2 to 3 months (standard diabetes biomarker).

Diagnostic & Lab Tests

eGFR

Estimated Glomerular Filtration Rate

Core biomarker evaluating kidney filtration function based on serum creatinine.

Diagnostic & Lab Tests

LFT

Liver Function Test

Measures hepatic enzymes (ALT, AST, ALP), bilirubin, and albumin to evaluate liver health.

Diagnostic & Lab Tests

KFT / RFT

Kidney / Renal Function Test

Measures blood urea nitrogen (BUN), serum creatinine, and electrolytes to assess renal filtration.

Diagnostic & Lab Tests

TSH

Thyroid-Stimulating Hormone

Pituitary hormone measured to screen for hypothyroidism (elevated) or hyperthyroidism (suppressed).

Diagnostic & Lab Tests

CRP

C-Reactive Protein

Acute-phase inflammatory marker elevated in systemic infections, autoimmune flares, and tissue injury.

Diagnostic & Lab Tests

ESR

Erythrocyte Sedimentation Rate

Non-specific rate of red cell sedimentation indicating systemic inflammation.

Diagnostic & Lab Tests

PT / INR

Prothrombin Time / International Normalized Ratio

Standardized measure of blood clotting speed, crucial for patients on warfarin or anticoagulant therapy.

Diagnostic & Lab Tests

ECG / EKG

Electrocardiogram

Records the electrical activity and conduction rhythms of the heart.

Diagnostic & Lab Tests

ECHO

Echocardiogram

Ultrasound imaging of the heart chambers, valves, and ventricular ejection fraction.

Diseases & Clinical Conditions

COPD

Chronic Obstructive Pulmonary Disease

Progressive inflammatory lung disease causing obstructed airflow from the lungs (emphysema, chronic bronchitis).

Diseases & Clinical Conditions

GERD

Gastroesophageal Reflux Disease

Chronic condition where stomach acid flows back into the esophagus, causing heartburn and mucosal irritation.

Diseases & Clinical Conditions

CHF

Congestive Heart Failure

Chronic condition in which the heart muscle is unable to pump sufficient blood to meet metabolic demands.

Diseases & Clinical Conditions

CKD

Chronic Kidney Disease

Long-term progressive loss of renal filtration function, staged from Stage 1 to Stage 5 (End-Stage Renal Disease).

Diseases & Clinical Conditions

DKA

Diabetic Ketoacidosis

Life-threatening acute metabolic complication of diabetes characterized by severe hyperglycemia, ketonemia, and acidosis.

Diseases & Clinical Conditions

DVT

Deep Vein Thrombosis

Blood clot formation within a deep vein, typically in the legs, carrying risk of pulmonary embolism.

Diseases & Clinical Conditions

PE

Pulmonary Embolism

Emergency blockage of one of the pulmonary arteries in the lungs by a displaced thrombus.

Diseases & Clinical Conditions

TIA

Transient Ischemic Attack

Brief episode of neurological dysfunction caused by focal brain ischemia without acute infarction ("mini-stroke").

Diseases & Clinical Conditions

STEMI

ST-Elevation Myocardial Infarction

Severe form of acute heart attack where a coronary artery is completely occluded, showing ST elevation on ECG.

Diseases & Clinical Conditions

IBS

Irritable Bowel Syndrome

Functional gastrointestinal disorder characterized by abdominal pain, cramping, bloating, gas, and altered bowel habits.

Vital Signs & Anatomy

BP

Blood Pressure

Systolic over diastolic arterial pressure (standard normal < 120/80 mmHg).

Vital Signs & Anatomy

HR

Heart Rate / Pulse

Number of heart contractions per minute (standard resting range 60–100 bpm).

Vital Signs & Anatomy

SpO2

Peripheral Capillary Oxygen Saturation

Estimation of the percentage of oxygenated hemoglobin in the blood (standard normal 95–100%).

Vital Signs & Anatomy

RR

Respiratory Rate

Breaths taken per minute (standard normal adult range 12–20 breaths/min).

Vital Signs & Anatomy

BMI

Body Mass Index

Weight-to-height ratio used as an anthropometric screening indicator of body mass (kg/m²).

Agencies & Regulatory

WHO

World Health Organization

United Nations agency specialized in international public health, guidelines, and disease surveillance.

Agencies & Regulatory

CDSCO

Central Drugs Standard Control Organization

India's national regulatory body for pharmaceuticals, medical devices, and clinical trials.

Agencies & Regulatory

FDA

Food and Drug Administration

United States federal agency responsible for protecting public health through the safety of drugs, foods, and biologics.

Agencies & Regulatory

EMA

European Medicines Agency

European Union agency responsible for the scientific evaluation and supervision of medicines.

Agencies & Regulatory

OTC

Over-The-Counter

Medicines sold directly to a consumer without a prescription from a healthcare professional.

This information is educational only and does not replace professional medical advice.