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FX classix

Proven Fresenius quality for standard hemodialysis

  • Proving track record of success of the Helixone membrane
  • Unique FX-class design
  • Purity enhanced — with steam
  • High endotoxin retention capacity


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Key features

Optimized blood flow conditions

  • The lateral blood-inlet port provides a homogenous blood flow in the dialyzer header, preventing stagnation zones. The design minimizes the risk of kinking, contributing to improved safety
  • A high capillary density leads to a more even distribution of the fibers. This ensures a homogenous distribution of the incoming blood flow into each fiber in the bundle

Homogeneous dialysate flow for better clearances

  • The pinnacle structure at both ends of the polypropylene housing together with the potting technology provides an even, radial flow of the dialysate around the individual fibers of the bundle
  • The undulation of the hollow fibers prevents dialysate channeling and, thus, enhances the performance of the dialyzer. The higher packing density of the fiber bundle together with the undulation of the hollow fibers enables a uniform dialysate flow within the whole cross-section of fiber bundle

The FX-class housing design

The FX-class housing design was optimized for efficient blood flow conditions

The FX-class design

The FX-class design affects dialysate flow and hence dialyser performance

Dialyzer weight

Dialyzer weight is a crucial factor not only in logistics but also in waste management. The housing of FX-class dialyzers is made of polypropylene. In comparison to the widely used polycarbonate it is much lighter with the result that FX-class dialyzers weigh around half as much as most dialyzers.

Dialyzer weight is a crucial factor not only in logistics but also in waste management. The housing of FX-class dialyzers is made of polypropylene. In comparison to the widely used polycarbonate it is much lighter with the result that FX-class dialyzers weigh around half as much as most dialyzers.
FX 60 classix 107g
FX CorDiax 60 107g

Weight of FX-class dialyzers

The benefits of INLINE steam sterilization

No chemical residuals No need for gamma sterilization – high energy ionizing radiation can degrade and alter the material chemistry. 
Low rinsing volumes Minimal preparation time – since dialyzers are clean on arrival, rinsing times prior to use are substantially reduced.  
Less rinsing – lower costs Lower rinsing volumes mean reduced preparation times and costs.


Better clearance through nanotechnology

Conventional pores

The removal of uraemic toxins is enhanced by smooth and cylindrical pores

Helixone pores

The removal of uraemic toxins is enhanced by smooth and cylindrical pores

NCSTM results in optimized pore size distribution and larger average pore size

When FX-class dialyzers were introduced into the market, an innovative spinning technology had been developed to produce its Helixone membrane. The so called Nano Controlled Spinning (NCSTM) technology allowed the production of highly-defined pore structures. Opposed to the previously produced conventional pores which were rugged and uneven in shape, the pores at the inner layer of the Helixone membrane are smooth and cylindrical. This reduces the resistance of the molecules when travelling through the pores and therewith allow for enhanced removal.

Optimized pore spectrum through nanotechnology

All Helixone membranes offer optimized sieving properties as the pore size distribution has been tightened compared to previously produced membranes as used e.g. in the F-series. The average pore size is larger compared to F-series dialyzers and the variance in pore sizes is smaller. This results in a better selective permeability for middle molecules, i.e. a more favorable β2-m / albumin sieving proportion.

INLINE steam sterilisation

The INLINE steam sterilisation process

Purity enhanced — with steam

All FX-class dialyzers are sterilized by the unique INLINE steam sterilization process: 

  1. Both the blood and the dialysate compartment of the dialyzers are rinsed continuously with steam at a temperature of or above 121°C for more a minimum of 15 minutes. Rinsing with hot steam and without chemicals results in extremely low levels of residuals in the dialyzer
  2. The dialyzer is rinsed with sterile water  
  3. Every dialyzer is tested for fiber integrity using a bubble-point test  
  4. The dialyzers are dried with warm, sterile air  
  5. Finally, after drying the blood inlet and outlet ports are closed

Benefits of the INLINE steam sterilization process

  • Highly pure, sterile and pyrogen-free dialyzers without any potentially harmful residuals from sterilization
  • Biocompatibility of membranes remains unaffected from sterilization
  • Optimized use of resources due to low rinsing volumes: Only 500 mL is required
  • Minimized risk of blood leakages and fiber ruptures due to 100% fiber integrity testing
  • Dry dialyzers with minimized risk of contamination due to microbial growth

Fibre integrity testing

All dialyzers have to pass the bubble point test. Here, sterile air is pressed into the dialysate compartment while the blood compartment contains sterile water. If any leakages were present in the membrane, air would pass through the membrane and create bubbles. This integrity test minimizes the risk of fiber ruptures and therewith the risk of blood leakages.

Endotoxin adsorption per cmmembrane surface area after 120 min in-vitro dialysis with contaminated dialysate1

High endotoxin retention capacity of Helixone

Weber et al. (2003) compared endotoxin adsorption capacity of different dialyzers.

The Helixone membrane of a FX 60 dialyzer had a higher endotoxin adsorption capacity compared to:

  • Gambro‘s Polyflux 140H - Polyethersulfone (Polyamid S)
  • Gambro‘s Nephral ST 400 - Polyacrylonitrile (AN69ST)
  • B.Braun‘s Diacap HI PS 18 - Alpha- Polysulfone

Performance data

FX classix High-Flux dialysers   FX 50 classix FX 60 classix FX 80 classix FX 100 classix
Clearance (QB = 300 mL/min) Molecular weight (Dalton)        
Cytochrome c 12,230 55 74 89 100
Inulin 5,200 72 95 113 122
Vitamin B12 1,355 137 162 185 201
Phosphate 132 204 225 244 253
Creatinine 113 224 243 259 264
Urea 60 253 266 279 280
Clearance (QB = 400 mL/min)          
Cytochrome c 12,230   76 92 105
Inulin 5,200   99 119 129
Vitamin B12 1,355   175 202 222
Phosphate 132   252 279 291
Creatinine 113   277 300 309
Urea 60   312 334 336
Ultrafiltration coeff. (mL/h x mm Hg)   27 38 53 68
Sieving coefficients          
Albumin 66,500 < 0.001
Myoglobin 17,053 0.1
β2-microglobulin 11,731 0.7
Inulin 5,200 1
In vitro performance: QD = 500 mL/min, QF = 0 mL/min, T = 37°C (ISO8637). Ultrafiltration coefficients: human blood, Hct 32 %, protein content 6 %.
Membrane material Helixone
Sterilisation method INLINE steam
Housing material Polypropylene
Potting compound Polyurethane
Units per box 24
Effective surface (m²)   1.0 1.4 1.8 2.2
K0A Urea   866 1,068 1,394 1,429
Priming volume (mL)   53 74 95 116
Article number   F00002385 F00002386 F00002387 F00002388
Related content

Designed to dialyze. Built for cardioprotection.

1 Weber V. et al., Blood Purification (2003); 21: 365.

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