How To Use Commas with Adjectives

It’s been a while since I wrote about commas—those confusing little punctuation marks that seemingly everyone has an opinion about. Because there are many ways commas can be used (and overused), I touch on the topic from time to time. This month’s topic is when—and when not—to use commas between adjectives.

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Adjectives modify or describe another word, typically a noun. Large, delicious, helpful, red…all of these words describe something else: a large dog, a delicious cheesecake, a helpful Qbank, a red wagon. I could do this all day! 

What about when more than one adjective is used to describe a noun? Do commas belong between them? Depends on how they relate to the noun.

The confident prepared PA student is ready to take his rotation exam.

The adjectives here are confident and prepared—both of these words independently describe our rockstar PA student (he is confident and he is also prepared). These types of adjectives are called coordinate adjectives, and they are typically separated by a comma. 

The confident, prepared PA student is ready to take his rotation exam.

So how do you know whether your adjectives are coordinate or not? There are two easy tests:

1. Add the word “and” between the adjectives. Does the sentence still make sense?
2. Change the order of the adjectives. Does the sentence still make sense?

In our example, we can say the confident and prepared PA student as well as the prepared, confident PA student and our sentence still makes sense.

What about adjectives that aren’t coordinate? This means one or more of the adjectives is essential to the noun’s meaning (it belongs with the noun as one unit). These adjectives don’t pass our two tests. What does this look like?

He was the restrained rear-seat passenger and has had a gradual onset of abdominal pain.

The words describing our passenger are restrained and rear-seat. In this case, rear-seat is essential to understanding something about our passenger: it describes his location in the car. Rear-seat passenger is one entire unit that is being described by restrained, so these two adjectives aren’t coordinate. But let’s verify this with our trusty tests:

1. He was the restrained and rear-seat passenger
2. He was the rear-seat, restrained passenger

Nope and nope. These adjectives don’t pass either test—no comma needed.

Time to try some on your own! Would you add commas between these adjectives?

The patient has a pink patent healthy-appearing stoma.

Our adjectives are pink, patent, and healthy-appearing, and they all describe the stoma. But do they independently describe the stoma (that is, are they coordinate)? Let’s try our tests:

1. The patient has a pink and patent and healthy-appearing stoma
2. The patient has a healthy-appearing, patent, pink stoma; The patient has a patent, healthy-appearing, pink stoma (I won’t keep adding possible combinations)

Test 2 can be misleading because we naturally like to put adjectives in a particular order, and color is usually one of the first things we describe. However, even though the examples in both tests sound a little weird, they still make sense. These adjectives are coordinate, and we should put commas between them.

The patient has a pink, patent, healthy-appearing stoma.

How about this example?

On physical exam, multiple serpiginous lines are noted.

Test 1: multiple and serpiginous lines
Test 2: serpiginous, multiple lines

Nope, these adjectives don’t pass the tests. Why? Because serpiginous is essential to understanding the type of lines noted, and multiple builds on the description of the serpiginous lines. The adjectives in this sentence aren’t coordinate, so no comma should go between them.

How about this one?

Generalized anxiety disorder is defined as excessive uncontrollable worry causing significant impairment on more days than not for at least 6 months.

Let’s try our two tests:

1. excessive and uncontrollable worry
2. uncontrollable, excessive worry

Yep, those work—add the comma. The worry is both excessive and uncontrollable, not uncontrollable worry that is excessive.

Generalized anxiety disorder is defined as excessive, uncontrollable worry causing significant impairment on more days than not for at least 6 months.

There you have it! Another lesson to help you get comfortable using commas. And here’s my usual disclaimer: these tips relate to formal, technical writing (hey those are coordinate adjectives)—don’t fret about commas in your day-to-day texts, social media posts, and casual emails. Anyone who picks on you for your grammar has too much time on their hands.