FACS Buffer

Dillon Corvino

PBS + FCS wash/staining buffer for flow cytometry (FACS), without EDTA.
Published

September 18, 2026

Protocol ID: BUF-FACS-BUF Version: v1.0 Author: Dillon Corvino Date: September 18, 2026

Purpose

This buffer is used for washing, resuspending, and handling cells during flow cytometry staining and sorting (FACS). It contains no EDTA, unlike MACS Buffer (BUF-MACS-BUF), so it is the correct choice for perfusion and for any step upstream of an EDTA-sensitive assay (e.g. collagenase digestion).

Linked protocols

  • MUS-SPL-DIS
  • MUS-LIV-DIG
  • MUS-LNG-DIG
  • MUS-BM-ISO
  • MUS-BLD-PRC
  • MUS-TMR-DIG

Working buffer composition

Typical preparation for 500 mL:

Component Stock concentration Volume for 500 mL Final concentration Notes
PBS 1x — 490 mL — Base buffer
FCS — 10 mL 2% (v/v) Heat-inactivated if required
Note

FACS Buffer and MACS Buffer (BUF-MACS-BUF) share the same PBS/FCS base — MACS Buffer additionally contains 2 mM EDTA. See BUF-MACS-BUF for that recipe.

Preparation

A. Preparation of stock (if applicable)

Not applicable — prepared directly as the working buffer.

B. Preparation of working buffer

  1. Start with sterile PBS 1x in an appropriate bottle.
  2. Add FCS to achieve 2% (v/v).
  3. Mix gently by inversion.
  4. If sterility is required, filter through a 0.22 um filter into a sterile storage bottle.
  5. Label clearly with buffer name, date of preparation, initials, and sterile/non-sterile status.

Storage and stability

  • Store at 4 °C.
  • Recommended use within 4–6 weeks, subject to internal QC and sterility checks.
  • Invert gently before use to resuspend any settled components.
  • Avoid repeated temperature cycling; prepare smaller working aliquots if accessed frequently.

Reagent details

Component Supplier Cat# Notes
PBS 1x [TBD] [TBD] Sterile, Ca2+/Mg2+-free recommended
FCS [TBD] [TBD] Heat-inactivated if required

Safety (brief)

  • Handle biological samples in FACS buffer according to institutional biosafety rules.
  • FCS is of animal origin and should be treated as a potential biohazard.

Version history

Version Date Author Change summary
v1.0 2026-09-18 Dillon Corvino Split out of BUF-FACS-MACS (formerly buf_facs_macs_buffer.qmd) so each buffer_id maps to exactly one recipe.