• In approx. 40% of the incidences anemia is caused by iron deficiency (= ID). In turn, preoperative iron-deficiency anemia (= IDA) is associated with an increase in morbidity and mortality as well as with the need for a blood transfusion.
• A successful preoperative treatment of IDA via iron supplementation requires a timely screening of iron deficiency, typically done by analyzing specific blood parameters. This however of course requires drawing a blood sample which further reduces the patients' blood volume and is in many cases stated as an inconvenient procedure.
• Measured in blood zinc protoporphyrin-IX (= ZnPP) is an established parameter to detect ID.
• This study aims to evaluate a prototype device detecting ZnPP non-invasively in the intact oral mucosa of surgical patients.
• Results from the non-invasive measurement will be compared to reference measurements of ZnPP from residual blood samples (HPLC analysis) as well as to other parameters including Hb level and iron profile (MCH [= mean corpuscular hemoglobin], MCV [= mean corpuscular volume], ferritin, transferrin, transferrin saturation, soluble transferrin receptor, CRP).

The non-invasive measurements will be performed using a prototype device based on fluorescence spectroscopical techniques. In brief, light (restricted wavelengths: 407 / 425nm) will be used to excite ZnPP molecules within the blood of the oral mucosa by means of an optical fibre prob. The outgoing fluorescence emission of the excited molecules will be analyzed using a spectrometer and converted to a ZnPP value [unit: µmol/mol heme] using mathematical transformations as well as spectral fitting.

This study compares the diagnostic performance of iron deficiency based on non-invasive measurements of Zinc protoporphyrin with results based on standard laboratory procedure (i.e. ZnPP measured in whole blood sample using HPLC) and blood values assessed during clinical routine, respectively.

If results of non-invasive and reference measurement techniques yield coinciding results, the non-invasive method could provide an improved mean to detect iron deficiency and thereby to improve treatment of patients suffering from iron deficiency anemia.

Inclusion Criteria:

• Age > 18 years

Exclusion Criteria:

• Patients who received a blood transfusion less than 8 weeks before examination
• Pregnancy

All patients preoperatively screened for anemia in the anemia walk-in clinic of the University Hospital Frankfurt that fit the inclusion criteria will be asked to participate in the study.