## 1 Introduction  
The frequency of complications associated with aseptic and scheduled maxillofacial surgery is 1% [1] by 5% [2] up to reported 33% [3]. These data refer to young people and it is known that with age the risk of inflammatory complications increases. Inflammation is an important and one of the most common complications observed in this type of surgery.  
When midface is operated on, the maxillary sinuses are filled with blood, which may be infected [4]. Postoperative swelling also needs to be considered after orthognathic surgery, as the result of the onset of an infection or a harmless postoperative reaction [5]. The only dangerous condition of mentioned series is a developing infection. It would be very valuable to know as early as possible about the inflammation. This would avoid disastrous symptomatic treatment with corticosteroids [6], which would suppress the symptoms of inflammation and allow the infection to develop secretly. In addition, it would be worth knowing before starting the surgery whether a clinically healthy patient undergoing the scheduled procedure has no hidden inflammation.  
The soluble urokinase-type plasminogen activator receptor (suPAR) is ultrasensitive marker aggressiveness of infectious conditions [7]. It was also proved that the concentration of suPAR holds an independent information for risk stratification of morphility and mortality [8; 9; 10; 11; 12]. This 64 kDa protein, intensively studied since 1991 which [PERSON] et al. [13], found that agent derived from phorbol 12-myristate 13-acetate (PMA)-stimulated U937 cells having a high affinity for uPA, has one major disadvantage. This issue is reflected in clinical trials, making it impossible to compare different age groups of patients. Serum suPAR levels depend on the patient's age and, more worryingly, increase with age [14; 15]. The sicker the patient becomes as age advances, the less clear the suPAR level is as an indication of inflammation going on in the patient's body. The level of this biomarker is high in sick patients but is also high in older patients.  
While the acute-phase reactant C-reactive protein (CRP) is commonly used as the gold standard inflammation marker both in the clinic and in life-course research [16], suPAR is a newer biomarker of inflammation [17], which appears to be correlated with chronic rather than acute inflammation. Although CRP and suPAR are positively correlated, they appear to capture different aspects of inflammation [18]. CRP and IL-6 did not evidence consistent associations at age but suPAR increases [19]. Elevated suPAR was associated with accelerated pace of biological aging across multiple organ systems, older facial appearance, and with structural signs of older brain age [20]. The serum concentration of soluble uPAR correlates with inflammation and accelerated biological aging. Individuals with high levels of soluble uPAR have a greater decline in cognitive function and physical activity [21]. Moreover, suPAR is postulates as even be biomarkers of biological aging [14].  
In the general population suPAR levels are higher in females and in young healthy individuals (a typical group of maxillofacial patients) are about 2.5 ng/mL (males) and 3.0 ng/mL (females). The suPAR level is affected by a lifestyle and risk factors and it increases with age [8; 22; 23]. Therefore it makes difficult any comparison of age varied groups. One would like to break free from this age-driven framework.  
The aim of this study is to find simple way to age independent presentation of suPAR serum level.