Commas and independent clauses
When a compound sentence consists of two independent clauses joined by a coordinating conjunction (and, but, or or nor), place a separating comma before the conjunction.
The patient comes in today with prior records, but I cannot find a problem list.
It was discussed with the patient that we will schedule the surgery as soon as possible, and we will attempt lysis of adhesions at the same time.
Note that each clause is independent; i.e., it can stand on its own as a complete sentence. In the example below, the second sentence is modified somewhat so that it is no longer an independent clause and therefore there is no period before the conjunction.
It was discussed with the patient that we will schedule the surgery as soon as possible and attempt lysis of adhesions at the same time.
Attempt lysis of adhesions is not a complete sentence.
Exception: According to the Gregg Reference Manual, there is an exception to this guideline. This exception does not appear to be included in the AHDI Book of Style; check facility/employer preferences.
EXCEPTION: If either clause of a compound sentence is short, the comma before the conjunction may be omitted.
The patient is currently well and she will return only on a p.r.n. basis.
Make sure the omission of the comma does not lead to confusion.
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