PBS vs DPBS: What’s the Difference?

PBS and DPBS are two of the most common wash and handling solutions in cell culture, and they are often used interchangeably. But they are not identical. This guide explains what each one is, how they differ, and when the difference actually matters.

What they have in common

Both PBS (phosphate-buffered saline) and DPBS (Dulbecco’s phosphate-buffered saline) are isotonic, phosphate-buffered salt solutions that hold pH near 7.4. Both are used to wash cells, dilute reagents, and keep cells in a stable environment during handling, and neither contains nutrients for growth. For the basics, see our guide on what PBS is.

How PBS and DPBS differ

• Salt balance: DPBS was defined by Renato Dulbecco with a specific set of salts. Standard PBS recipes vary a little more from lab to lab.
• Calcium and magnesium: both are commonly offered in two versions, with or without Ca and Mg. This choice usually matters more than the PBS-vs-DPBS label itself.

When the difference matters

For routine washing, PBS and DPBS are usually interchangeable. The choice that actually affects results is whether the solution contains calcium and magnesium:

• Without Ca/Mg: preferred before enzymatic detachment such as trypsinization, because those ions support cell adhesion and can slow dissociation.
• With Ca/Mg: used when you need to preserve certain cell-surface interactions or downstream steps that depend on those ions.

So when a protocol specifies PBS or DPBS, the more important question is usually whether it wants the calcium- and magnesium-free version.

Which should you use?

Follow your protocol. If it simply says “PBS,” a standard PBS or DPBS will generally work for washing. Match the calcium and magnesium status to the step, and keep the same product across an experiment for consistency.