Most people feel free of symptoms at a ferritin value of 100-200 ng/ml (Beckman Coulter method). However, humans are not machines. Some people also feel healthy at a ferritin value below 50 ng/ml. Others meanwhile require a value of over 150 ng/ml to be asymptomatic. This individuality is taken into account in SIS. Doses are therefore calculated according to the adage: As much as necessary and as little as possible (principle of marginal benefit).
The Swiss Iron System SIS was developed in Switzerland between 1998 and 2005 following the discovery of iron deficiency syndrome. The initial objective was to identify patients who really need iron while ensuring that other medical problems are not overlooked.
The most difficult task was to discover the optimum individual dose required for sustainable successful therapy, according to the principle of marginal benefit: As much as necessary and as little as possible. As a result of this treatment, most affected patients feel free of symptoms or at least considerably better after only four weeks.
The SIS is divided into three phases:
Saturation therapy (T1 – T2)
For effective treatment, initially a saturation therapy is performed (following a substantiated diagnosis). The therapeutic success of this treatment is documented and assessed two weeks later (approx. four weeks after the start of treatment). In patients treated according to SIS, the ferritin value two weeks after the last infusion with iron sucrose is 200 ng/ml (the same as in adult males).
On average, a female of menstruating age requires approx. 0.9 grams of iron for successful saturation therapy (ideally 200 mg twice a week).
Observation phase (T3 – T4)
Following successful treatment, a further follow-up observation must take place to reassess the patient’s condition. On average, the ferritin value in females of menstruating age after three regular periods (three months later) is 140 ng/ml. At this stage, nearly all report still feeling healthy. On average, the first relapse symptoms occur when the ferritin value falls below 100 ng/ml (Beckman method) or 150 ng/ml (Roche method).
Maintenance therapy (after T4)
Once the ferritin threshold value below which the “familiar” iron deficiency symptoms begin to reappear is known, the quantity of iron that is required per year to avoid a relapse must be calculated (divided into practical intervals).
For a sustainably effective maintenance therapy, a women needs an average of approx. one gram of iron per year, administrated in individually calculated single doses at suitable intervals.
T1: Appointment 1
- Diagnosis (documentation of laboratory values and symptoms)
- Precise calculation of the individual required iron dose and selection of the optimal preparation for the saturation therapy
T2: Appointment 2
- First follow-up check 2-3 weeks after the final infusion (documentation of changes to laboratory values and symptoms)
T3: Appointment 3
- Second follow-up three months later for quality control and checking sustainability (documentation of changes to laboratory values and symptoms)
T4: Appointment 4
- Third follow-up check three months later, or before if relapse symptoms occur (documentation of changes to laboratory values and symptoms)
- Definition of individual optimum range
- Planning and calculation of dose for maintenance therapy
T5: Appointment 5 and later follow-ups
- Further follow-up checks coordinated with the maintenance doses to be administered individually.