Evaluation of non cyanide methods for hemoglobin estimation

The hemoglobincyanide method (HiCN) method for measuring hemoglobin is used extensively worldwide; its advantages are the ready availability of a stable and internationally accepted reference standard calibrator. However, its use may create a problem, as the waste disposal of large volumes of reagent containing cyanide constitutes a potential toxic hazard.

As an alternative to drabkin`s method of Hb estimation, we attempted to estimate hemoglobin by other non-cyanide methods: alkaline hematin detergent (AHD-575) using Triton X-100 as lyser and alkaline- borax method using quarternary ammonium detergents as lyser.

The hemoglobin (Hb) results on 200 samples of varying Hb concentrations obtained by these two cyanide free methods were compared with a cyanmethemoglobin method on a colorimeter which is light emitting diode (LED) based. Hemoglobin was also estimated in one hundred blood donors and 25 blood samples of infants and compared by these methods. Statistical analysis used was Pearson`s correlation coefficient.

The response of the non cyanide method is linear for serially diluted blood samples over the Hb concentration range from 3 gm/dl -20 gm/dl. The non cyanide methods has a precision of + 0.25 g/dl (coefficient of variation= (2.34%) and is suitable for use with fixed wavelength or with colorimeters at wavelength- 530 nm and 580 nm. Correlation of these two methods was excellent (r=0.98). The evaluation has shown it to be as reliable and reproducible as HiCN for measuring hemoglobin at all concentrations. The reagents used in non cyanide methods are non-biohazardous and did not affect the reliability of data determination and also the cost was less than HiCN method.

Thus, non cyanide methods of Hb estimation offer possibility of safe and quality Hb estimation and should prove useful for routine laboratory use. Non cyanide methods is easily incorporated in hemoglobinometers by using very minute quantities of reagents and test sample; hence, these methods can be used to provide point of care testing in blood banks for hemoglobin (Hb) estimation in blood donors.