Feasibility of Measuring Autofluorescence of Red Blood Cells Utilizing a Novel Flow Cytometer to Define Iron Deficiency Patients

• Feasibility of Measuring Autofluorescence of Red Blood Cells Utilizing a Novel Flow Cytometer to Define Iron Deficiency Patients

AUTHOR(S)

Kazuhiro YAMADA^*１, Takeshi YAMAMOTO^*１, Kazuhiro SASAKI^*１, Andreas Robert HUBER^*２, Saskia Brunner-AGTEN^*２

*1 Sysmex Corporation
*2 Institute of Laboratory Medicine, Kantonsspital Aarau

SUMMARY

Several different indices have been proposed for differentiating microcytic anemia. These indices are based on RBC parameters which are provided from a hematology analyzer. Zinc protoporphyrin IX ( ZnPP ) is also used for the screening of microcytic anemia, especially for iron deficiency anemia ( IDA ), because ZnPP and metal-free protoporphyrin IX ( PPIX ) are found at elevated levels in RBCs if heme production is inhibited by lack of iron. It is well known that ZnPP and PPIX in red blood cells emit autofluorescence through excitation by blue-violet light. The aim of this study is to assess new rapid and precise method for screening IDA with autofluorescence from red blood cells detected by customized XN hematology instruments.

The customized XN used in this study has two kinds of laser. In addition to standard 640nm laser, the instrument was equipped with a 405nm laser. Further, two additional detectors, one for detecting 405nm forward light scatter signals and another for detecting the fluorescence excited by 405nm laser, were mounted on the instrument. When RBC is excited by 405nm laser, autofluorescence from RBC in IDA samples can be detected on the customized XN.

The intensity of autofluorescence from red blood cells was measured on the customized XN for a set of 16 non-anemia samples and 19 samples with IDA. Autofluorescence signal intensity in IDA samples was much higher than in non-anemia samples. Further, we found a positive correlation between autofluorescence and ZnPP levels.

The customized XN can provide information of iron deficiency as well as common hematology parameters. We expect that this inexpensive and simple approach will be a cost effective alternative to current procedures particularly in developing countries.

KEY WORDS

Autofluorescence, Iron Deficiency Anemia, Thalassemia, Zinc Protoporphyrin, New Instrument