FIX&PERM® Cell Fixation and Permeabilization Kits for Intracellular Flow Cytometry
The Industry-Standard Two-Reagent Kit for Intracellular Staining in Flow Cytometry
FIX&PERM® is a simple, two-step cell preparation kit that opens the cytoplasm and nucleus to fluorochrome-labeled antibodies — without compromising the surface markers or scatter characteristics that flow cytometry depends on. Reagent A gently fixes cells. Reagent B permeabilizes them. Together they make intracellular antigens, cytokines, oncoproteins, and immunoglobulins accessible for staining in whole blood, bone marrow, or mononuclear cell preparations.
Originally characterized by Knapp et al. (1994) and cited in hundreds of peer-reviewed publications since, the FIX&PERM kit remains the reference method many flow cytometry labs reach for first when they need to combine surface and intracellular staining in a single workflow.
FIX & PERM is manufactured by our partner brand Exalpha Biologicals, a Vector Laboratories company. Vector Labs customers can access the full FIX&PERM family through Exalpha.
Why Choose FIX&PERM® for Intracellular Flow Cytometry Staining?
Mild Fixation, Preserved Scatter
Mildly fixes cells, preserving their flow cytometric scatter characteristics
Surface and Intracellular in One Run
Allows simultaneous characterization of both intracellular and cell surface markers
Rapid
Whole procedure can be carried out in less than one hour, ready for immediate analysis or storage for 24 hours
Proven, Validated, and Cited
Initially characterized in Knapp et al. in 1994, independently validated in studies such as Groeneveld et al. in 1996 and Lanza et al. in 1997, and cited in hundreds of peer-reviewed publications since
Stringent Lot-to-Lot QC
The quality of each lot is confirmed using well-defined blood samples and subsequent comparison of scatter characteristics and immunostaining patterns, ensuring consistent and reliable results each time
Stable, Solvent-Free Formulation
Our formulations do not contain volatile organic solvents, enabling storage at ambient temperature during shipment and in laboratories
Flexible
Can be used with most monoclonal antibody conjugates, as well as our range of antibodies with optimized protocols for use with FIX&PERM®
CE/IVD registered kits available for European customers in a clinical laboratory setting (contact us for further information)
FIX & PERM Protocol for Intracellular Flow Cytometry Staining
Per sample: 50 µL of whole blood, bone marrow, or mononuclear cell suspension in a 5 mL tube.
- Add 100 µl of Reagent A (Fixation Medium, stored and used at room temperature)
- Incubate for 15 minutes at room temperature
- Add 5 ml phosphate buffered saline and centrifuge cells for 5 minutes at 300 g
- Remove supernatant and add to cell pellet 100 µl Reagent B (Permeabilization Medium) and 20 µl of the appropriate monoclonal antibody conjugate
- Vortex at low speed for 1-2 seconds
- Incubate for 15 minutes at room temperature
- Wash cells with phosphate buffered saline as described above
- Remove supernatant and resuspend cells in sheath fluid for immediate analysis or resuspend cells in 0.5 ml 1.0 % formaldehyde and store at 2-8°C in the dark
- Analyze fixed cells within 24 hours
FIX&PERM® Products
Choose the FIX&PERM format that fits your throughput and workflow. All products link to the corresponding Exalpha product page for ordering.
| Catalog Code | Product Name | Product Type |
| GAS-002 | FIX&PERM® Cell Fixation and Permeabilization Kit | Buffers and Reagents |
| GAS-002-1 | FIX&PERM® Kit 1000 | Buffers and Reagents |
| GAS-002A-1 | FIX&PERM® Solution A (Fix) | Buffers and Reagents |
| GAS-002B-1 | FIX&PERM® Solution B (Perm) | Buffers and Reagents |
| GAS-002M | FIX&PERM® Sample Kit | Buffers and Reagents |
Antibodies Optimized for Use with FIX&PERM®
Most monoclonal antibody conjugates can be used with FIX&PERM® directly. For convenience, the following mouse anti-human PE/FITC conjugates are pre-validated for FIX & PERM workflows and ship with optimized protocols.
| Antigen | Clone | Isotype | Format | Quantity | Cat. No. |
| CD3 | UCHT1 | IgG1 | Purified | 0.2 mg | GM-4011 |
| CD3 | UCHT1 | IgG1 | FITC-labeled | 100 tests | GM-4012 |
| CD3 | UCHT1 | IgG1 | PE-labeled | 100 tests | GM-4013 |
| CD22 | RFB4 | IgG1 | Purified | 0.2 mg | GM-4051 |
| CD22 | RFB4 | IgG1 | FITC-labeled | 100 tests | GM-4052 |
| CD22 | RFB4 | IgG1 | PE-labeled | 100 tests | GM-4053 |
| Lactoferrin | 4C5 | IgG1 | Purified | 0.2 mg | GM-4111 |
| Lactoferrin | 4C5 | IgG1 | PE-labeled | 100 tests | GM-4113 |
| Myeloperoxidase | 8E6 | IgG1 | Purified | 0.2 mg | GM-4191 |
| Myeloperoxidase | 8E6 | IgG1 | FITC-labeled | 100 tests | GM-4192 |
| Myeloperoxidase | 8E6 | IgG1 | PE-labeled | 100 tests | GM-4193 |
| Lysozyme | LZ-2 | IgG1 | Purified | 0.2 mg | GM-4131 |
| Lysozyme | LZ-2 | IgG1 | FITC-labeled | 100 tests | GM-4132 |
| CD68 | Ki-M7 | IgG1 | FITC-labeled | 100 tests | GM-4152 |
FIX&PERM® Combi Panels for Dual Immunostaining
Pre-paired FITC and PE conjugates for dual-color intracellular staining protocols using FIX&PERM®.
| Antigen Pair | Clone(s) | Isotype | Format | Cat. No. |
| Negative control IgG1 (FITC + PE) | Vl-AP | IgG1 | FITC + PE | GIC-201 |
| Lysozyme (FITC) + Lactoferrin (PE) | LZ-2 / 4C5 | IgG1 | FITC + PE | GIC-206 |
| Myeloperoxidase (FITC) + Lactoferrin (PE) | 8E6 / 4C5 | IgG1 | FITC + PE | GIC-212 |
| Myeloperoxidase (FITC) + CD3 (PE) | 8E6 / UCHT1 | IgG1 | FITC + PE | GIC-213 |
| Myeloperoxidase (FITC) + CD22 (PE) | 8E6 / RFB4 | IgG1 | FITC + PE | GIC-214 |
