A free guide to the clinical abbreviations every healthcare student needs, organized by category — dosing frequency, routes, vitals, charting, imaging, and labs.
| Term / Abbreviation | Meaning |
|---|---|
| BID | Twice a day (bis in die) |
| TID | Three times a day (ter in die) |
| QID | Four times a day (quater in die) |
| QD / daily | Once a day (quaque die — write 'daily' to avoid confusion) |
| QOD | Every other day (quaque altera die) |
| QH | Every hour (quaque hora) |
| Q4H, Q6H, Q8H | Every 4 / 6 / 8 hours |
| HS | At bedtime (hora somni) |
| AC | Before meals (ante cibum) |
| PC | After meals (post cibum) |
| PRN | As needed (pro re nata) |
| STAT | Immediately (statim) |
| Term / Abbreviation | Meaning |
|---|---|
| PO | By mouth (oral) (per os) |
| PR | Per rectum |
| SL | Sublingual (under the tongue) |
| TOP | Topical |
| INH | Inhaled |
| IV | Intravenous |
| IM | Intramuscular |
| SubQ / SC | Subcutaneous |
| ID | Intradermal |
| NPO | Nothing by mouth (nil per os) |
| Term / Abbreviation | Meaning |
|---|---|
| BP | Blood pressure |
| HR | Heart rate |
| RR | Respiratory rate |
| T | Temperature |
| SpO2 | Oxygen saturation (pulse oximetry) |
| VS | Vital signs |
| WNL | Within normal limits |
| I&O | Intake and output |
| BMI | Body mass index |
| wt / ht | Weight / height |
| Term / Abbreviation | Meaning |
|---|---|
| SOB | Shortness of breath |
| DOE | Dyspnea on exertion |
| CP | Chest pain |
| N/V | Nausea and vomiting |
| LOC | Loss of consciousness / level of consciousness |
| AMS | Altered mental status |
| AAOx3 / AAOx4 | Awake, alert, and oriented to person/place/time(/situation) |
| ROM | Range of motion |
| ADL | Activities of daily living |
| DNR | Do not resuscitate |
| Term / Abbreviation | Meaning |
|---|---|
| Hx | History |
| Sx | Symptoms |
| Dx | Diagnosis |
| Tx | Treatment |
| Rx | Prescription / therapy |
| Fx | Fracture |
| PMH | Past medical history |
| PSH | Past surgical history |
| FH | Family history |
| SH | Social history |
| HPI | History of present illness |
| ROS | Review of systems |
| PE | Physical exam |
| A&P | Assessment and plan |
| Term / Abbreviation | Meaning |
|---|---|
| CXR | Chest X-ray |
| CT | Computed tomography |
| MRI | Magnetic resonance imaging |
| US | Ultrasound |
| ECG / EKG | Electrocardiogram |
| EEG | Electroencephalogram |
| EGD | Esophagogastroduodenoscopy |
| TTE | Transthoracic echocardiogram |
| PFT | Pulmonary function test |
| ABG | Arterial blood gas |
| Term / Abbreviation | Meaning |
|---|---|
| CBC | Complete blood count |
| BMP | Basic metabolic panel |
| CMP | Comprehensive metabolic panel |
| LFT | Liver function tests |
| TSH | Thyroid stimulating hormone |
| BUN | Blood urea nitrogen |
| Cr | Creatinine |
| INR | International normalized ratio (clotting) |
| HbA1c | Hemoglobin A1c (3-month average glucose) |
| UA | Urinalysis |
BID (twice a day), TID (three times a day), PRN (as needed), NPO (nothing by mouth), STAT (immediately), PO (by mouth), IV (intravenous), and IM (intramuscular) are among the most frequent — they appear on virtually every chart.
PRN stands for 'pro re nata,' Latin for 'as needed.' It indicates a medication or intervention should be given when a specific condition arises (such as pain or nausea), rather than on a fixed schedule.
NPO stands for 'nil per os,' Latin for 'nothing by mouth.' It means the patient should not eat or drink anything — typically before surgery, certain procedures, or when there's a risk of aspiration.
Yes. The Institute for Safe Medication Practices maintains a 'Do Not Use' list. Common examples include U (mistaken for 0), QD (confused with QID), and MS (ambiguous between morphine sulfate and magnesium sulfate). Always follow your facility's approved list.
BID = twice a day, TID = three times a day, QID = four times a day. They come from Latin (bis/ter/quater in die) and are used in dosing instructions for scheduled medications.
Reading them on charts, orders, and handoffs builds fluency fastest. Our interactive medical terminology games include scenarios that drop these abbreviations into realistic clinical contexts so you build automatic recognition.