Non-invasive Diagnostics of Iron Deficiency in Surgical Patients by Measuring Zinc Protoporphyrin-IX

Study Overview
=================
Brief Summary
-----------------
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).

Detailed Description
-----------------
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.

Official Title
-----------------
Non-invasive Diagnostics of Iron Deficiency in Surgical Patients by Measuring Zinc Protoporphyrin-IX

Conditions
-----------------
Iron-deficiency, Anemia, Iron Deficiency Anemia

Intervention / Treatment
-----------------
* Diagnostic Test: Non-invasive analysis of Zinc protoporphyrin


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age > 18 years Exclusion Criteria: Patients who received a blood transfusion less than 8 weeks before examination Pregnancy

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Study Group<br>Detecting iron deficiency using various methods. All patients that fit the inclusion criteria and are willing to participate in the study will be included in this group. | Diagnostic Test: Non-invasive analysis of Zinc protoporphyrin<br>* In patients fitting the inclusion criteria Zinc protoporphyrin will be measured non-invasively as proxy for iron deficiency. Results will be compared to ZnPP reference values measured via HPLC and with spectroscopical measurements performed on whole blood as well as with blood values (HB, MCH, MCV, ferritin, CRP, transferrin saturation, soluble transferrin receptor) assessed during clinical routine.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Zinc protoporphyrin blood concentration (non-invasive measurement) | Using the prototype device Zinc protoporphyrin blood concentration [unit: µmol/mol heme] will be measured non-invasively in the oral mucosa. Concentrations will be compared (Spearman's Rho, sensitivity, specificity) with Zinc protoporphyrin measurements of whole blood samples (see outcome 2 and 3). | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Zinc protoporphyrin blood concentration (HPLC reference measurement) | Using HPLC, the analytical reference method, Zinc protoporphyrin blood concentration [unit: µmol/mol heme] will be measured in whole blood samples. | Baseline | 
| Zinc protoporphyrin blood concentration (spectroscopic measurement) | Using fluorescence spectroscopic methods Zinc protoporphyrin blood concentration [unit: µmol/mol heme] will be measured in whole blood samples. | Baseline | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Iron-deficiency, Anemia, Iron-deficiency Anemia, Zinc protoporphyrin