A Preliminary work on Non Invasive Technique for Measurement of Hemoglobin

Hemoglobin (Hb) is the most important vital parameter of red blood cells. Its level in human body is a vital analytic parameter for diagnosing anemia in both long-term and severe conditions. At present, invasive techniques are employed to quantify the Hemoglobin absorption, by which blood is sampled out from the patient and followed by laboratory analysis. Besides from the irritation of taking blood samples, an additional disadvantage of this technique is the time delay between the collection of blood samples and its analysis, which is not suitable for real time patient monitoring under severe condition and rural area with inadequate testing facility. This paper presents an optical non-contact technique that provides Hb concentration measurement. The absorbent coefficient of blood differs at different wavelength this certainty is used to determine the optical property of blood. In this newly developed system, absorption of light by oxygenated and deoxygenated hemoglobin is measured at two wavelength 660nm and 940nm. The particular wavelength of light is obtained from red and IR LED. Constant current circuit is designed to drive the LEDs. Transmitted light through an area of skin on finger was detected by a photodiode. Ratio of Red LED to IR signal after normalization is calculated for determination of Hemoglobin. Signal acquisition by this technique is totally noninvasive.