Reference

Medical abbreviations list

A quick-reference guide to the 34 short forms doctors and clinic staff write in case papers, prescriptions, and clinical notes — from Dx and Rx to dosing instructions like BD, TDS, and PRN. Each entry lists the full meaning and how it is used.

History & examination

Shorthand used while taking the patient history and documenting the clinical examination in the case sheet.

Short form	Meaning	Typical use
CC	Chief Complaint	Main reason for the visit
HPI	History of Present Illness	Details of the current problem
Hx	History	Patient history, general
PMH	Past Medical History	Previous diseases and conditions
FH	Family History	Relevant conditions in the family
SH	Social History	Smoking, alcohol, occupation, etc.
ROS	Review of Systems	Symptoms across body systems
O/E	On Examination	Examination findings
PE	Physical Examination	Physical exam

Vital signs

The core measurements recorded at almost every visit.

Short form	Meaning	Typical use
V/S	Vital Signs	BP, pulse, temperature, SpO₂
BP	Blood Pressure	Vital sign
HR	Heart Rate	Vital sign
RR	Respiratory Rate	Vital sign
SpO₂	Oxygen Saturation	Blood oxygen level, read by pulse oximeter

Diagnosis & treatment

Terms used to record the assessment, plan, and outcome of a consultation.

Short form	Meaning	Typical use
Dx	Diagnosis	Doctor's clinical diagnosis
DDx	Differential Diagnosis	Possible alternative diagnoses
Rx	Prescription	Medicines prescribed
Tx	Treatment	Overall treatment plan
Px	Prognosis	Expected outcome
F/U	Follow-up	Next visit or check

Dosing instructions

Urgency and special-condition instructions written on prescriptions and orders.

Short form	Meaning	Typical use
PRN	As Needed	Take only when required (Latin: pro re nata)
STAT	Immediately	Urgent, give at once (Latin: statim)
NPO	Nothing by Mouth	Before procedures or surgery (Latin: nil per os)

Dose frequency

How often a medicine should be taken. Both Latin and English short forms are common.

Short form	Meaning	Typical use
OD	Once Daily	Medication frequency
BD / BID	Twice Daily	Medication frequency (Latin: bis in die)
TDS / TID	Three Times Daily	Medication frequency (Latin: ter in die)
QID	Four Times Daily	Medication frequency (Latin: quater in die)
HS	At Bedtime	Medication timing (Latin: hora somni)
AC	Before Meals	Medication timing (Latin: ante cibum)
PC	After Meals	Medication timing (Latin: post cibum)

Routes of administration

How a medicine enters the body.

Short form	Meaning	Typical use
PO	By Mouth	Oral route (Latin: per os)
IM	Intramuscular	Injection into muscle
IV	Intravenous	Injection or infusion into a vein
SC / SQ	Subcutaneous	Injection under the skin

Frequently asked questions

What does Rx mean in medical terms?

Rx is the abbreviation for "prescription" — the medicines a doctor prescribes. It comes from the Latin word "recipe", meaning "take".

What is the difference between Dx, DDx, Tx and Px?

Dx means diagnosis (the identified condition), DDx means differential diagnosis (the list of possible alternative diagnoses), Tx means treatment (the overall plan), and Px means prognosis (the expected outcome).

What do BD, TDS, QID and OD mean on a prescription?

These describe dose frequency. OD is once daily, BD (or BID) is twice daily, TDS (or TID) is three times daily, and QID is four times daily.

What does PRN and STAT mean?

PRN (Latin "pro re nata") means "as needed" — take the medicine only when required. STAT (Latin "statim") means "immediately" — give at once, used for urgent orders.

Looking for full definitions? Browse the clinic software glossary

This reference is for general information. Abbreviation conventions can vary between clinics and regions, and some short forms are discouraged in safety-critical settings — always follow your own institution's documentation standards.