Why Do Med Assistants Take Vital Signs

Learn More

Take the first step toward a fulfilling career in healthcare.

By requesting information, I consent, without obligation, to be contacted by PCI Health via email, telephone, and text, using automated technology, at any telephone number and email address that I provide.

Medical Assistants Take Vital Signs

Vital signs are clinical measurements of the body’s essential functions. These readings help doctors diagnose disease and other medical conditions. Performed by a medical assistant, it’s a routine but critical task that requires technical expertise, skill, and accuracy.

What Are the Different Vital Signs?

The four principal vital signs are temperature, blood pressure, pulse, and respiratory rate. Measures of clinical significance, including height, weight, and peripheral oxygen saturation, aren’t always a part of vital signs in all doctor’s offices; it depends on their specialty. Oxygen saturation is the percentage of oxygen in peripheral tissue and is a more valuable indicator of health as part of a cardiac workup than a gynecological exam.

When Does a Medical Assistant Take Vital Signs?

Medical assistants take vital signs at each visit. Changes in temperature, blood pressure, pulse and respirations can indicate an acute illness, but patterns over time are even more telling. A single elevated blood pressure reading, for example, is rarely clinically significant on its own, but an up or down trend over months could indicate a serious disorder.

How Are Vital Signs Taken?

Medical assistants take vital signs using the latest equipment and these methods:


The normal adult body temperature is variable. 98.6 is only an average. The healthy range is between 97 and 99 degrees Fahrenheit. Temperature is measured orally, rectally, tympanic, and on skin.

Blood Pressure

Blood pressure is the force blood exerts on artery walls during a two-part cardiac cycle. Systolic blood pressure, measured when the heart beats, reflects the strength of the muscle. It’s reported “over” the diastolic measurement, which is taken when the heart is relaxed. Together readings paint a picture of the patient’s cardiovascular function.

A medical assistant takes a patient’s BP with a sphygmomanometer, a device that measures the rise and fall of a column of mercury as air is added to, or released from, a cuff wrapped around the upper arm. The medical assistant records results as millimeters of mercury, or “mm Hg.”


Arteries vibrate with every heartbeat. Medical assistants measure heart rate, or “pulse,” over the arteries in the wrist, neck or groin by counting the pulsations for 15 seconds and multiplying the result by four.

The rhythm and character of the beats are also noted. Patients with abnormal heart rates or rhythms require special care. Medical assistants use a stethoscope to listen to heartbeats directly because it’s easier to detect abnormalities.

Respiratory Rate

A patient’s respiratory rate is how many breaths they take in 60 seconds, adults average 12–16. Stress and anxiety can cause unexpected changes in how people breathe, so medical assistants count while making chit chat, so patients are unaware.


Medical assistants measure height in inches or centimeters against a vertical surface. Using the same device and a consistent technique at each visit ensures accuracy.


Medical assistants obtain weight in pounds or kilograms using a standing scale. A few pounds gained or lost can be clinically significant, so precision counts.

Peripheral Oxygen Saturation

Oxygen saturation readings indicate how much hemoglobin, the oxygen-carrying substance in blood, is reaching the brain and peripheral tissues. Readings are taken with a pulse oximeter that clamps to the patient’s fingertip. The medical assistant records results as a percentage. 95 to 100 is normal. Cold fingers and dark nail polish may cause abnormally low results.

Why Are Vital Signs Taken

Taking vital signs at every visit gives doctors a wealth of information that serves several important purposes.

It Establishes a Baseline

Changes in a patients’ vital signs can only be detected if they’ve been regularly monitored. Readings vary between individuals, and it’s essential not to make treatment decisions without knowing what’s normal for each patient.

It Can Diagnose Illness and Disease

A change in vital signs is often the first indicator of an acute illness. Specific patterns are recognized as indicative of certain conditions. An elevated temperature, pulse and respiratory rate, for example, may suggest infection.

Doctors use trends over time to diagnose disease. A few high blood pressure readings could be flukes, but if it remains elevated, it reflects hypertension, a primary disorder often rooted in heart or kidney disease. Accurate vital signs tell the doctor what to look for and what steps to take.

It’s Used to Calculate and Adjust Medication Dosages

Many medications are prescribed based on:

Heart Rate – Drugs for abnormal heart rhythms can lower heart rate too much. Patients on these medications are asked to check their pulse daily before taking a dose, adjusting it up or down based on rate.

Blood Pressure – Many people’s blood pressure is too variable for a preset dose of antihypertensive drugs, so instead, physicians prescribe a range of BP-related doses. These patients monitor their readings at home and take more or less medication based on the results.

BMI – Also known as body mass index, this reading is used to calculate dosage for a wide range of medications, from antibiotics to anticoagulants. BMI is a calculation using a patient’s height and weight, so those measurements must be accurate.

Oxygen Saturation – Levels are used to determine if someone needs supplemental oxygen or breathing medications. Dosages can be tricky because many people with respiratory issues also have heart disease, and doses for each condition vary. It’s a balancing act made safer by taking vital signs.

Final Thoughts

Medical assistants perform a broad range of administrative and clinical functions, but among the most meaningful is taking timely, accurate vital signs. These essential measures are a window into a patient’s health and a must for physicians to make sound, therapeutic decisions.

Did learning about taking vital signs interest you? Ready to become a medical assistant? PCI Health Training Center’s Medical Assistant program prepares a graduate to work as an entry-level Medical Assistant. Within this general career category there are several specialty areas, including Medical Administrative Office Assistant, Clinic Assistant, Clinic Tech, Medical Office Manager, Phlebotomist and Physical Therapy Aide in a doctor’s office, clinic or hospital out-patient clinic. Contact PCI Health Training Center for more information on how to become a medical assistant and start a rewarding career today.

**PCI firmly upholds its policy of nondiscrimination. Inquiries regarding policy may be directed to TitleIXCoordinator@pcihealth.com.

For more information about our graduation rates and other important information, please visit our website at www.pcihealth.edu/consumer-information.