A new method for measuring hemoglobin.
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ABSTRACT: Among the colorimetric methods of haemoglobin estimation Cyanmethemoglobin method is commonly used. A new colorimetric method developed by the author, using acid–haematin is also having been found to be similar sensitivity 1 . In both methods red cells are haemolysed and released haemoglobin form complex with respective chemicals that give optical density that is measured during estimation of haemoglobin but in both methods, leucocytes have no way to be lysed or are not eliminated from the chemicals. These leucocytes should have definite optical density and though in normal range of population, blood leucocytes do not confer any significant optical density interfering absorbance during hemoglobin estimation but very high leucocytes count (e.g., in leukemia) should mis-interpretate actual hemoglobin level due to showing significant optical density. For over five years hemoglobin levels were estimated from 14400 patients out of whom 118 blood samples were of leukemia and 4 were leukemoid reaction with leucocytes ranging from count 50,000/cumm to 6,00,000/cumm. On average leucocytes 50,000 /cumm of blood found to falsely increase haemoglobin level to 0.55gm% of blood.Northern Medical Journal. 03/2006; 15(1-1):9-12.
Estimation of hemoglobin level is one of the most com-
mon laboratory tests. For economic reasons, Sahli’s acid
hematin method, although least accurate among all methods,
is still being used in many laboratories, particularly in devel-
oping countries. Keeping the cost almost the same, I have
developed and standardized the acid hematin method into a
colorimetric (photoelectric) method that is as accurate as the
In this new method, 200 µL 1.5% HCl (vol/vol) solu-
tion is placed in a test tube and 20 µL blood (preferably
venous) is mixed with the solution, which is then left undis-
turbed for at least 3 minutes. Then 5 mL distilled water is
added to the test tube and absorbance is taken with a photo-
electric colorimeter (filter 530 nm) or autoanalyzer/spec-
trophotometer (547 nm) after 5 minutes against distilled
water as blank. Acid hematin standard solution prepared
with preservatives can be used, but is not cost effective. An
alternative artificial standard with more stability also has
been prepared, but the cyanmethhemoglobin standard can
be used as a secondary standard.
It is interesting that absorbances for blood samples have
been found to be the same in both the cyanmethhemoglobin
method and my modified method. This similarity limits the
use of a separate standard for the new method. Many factors
affect both methods in the same way, but during my study I
found a new factor, high white blood cell (WBC) count, that
significantly interferes with both methods (1.2 to 1.4 gm%
increase in hemoglobin level per 0.1 million/µL WBC
count). To avoid this problem, supernatant solution must be
used during the absorbance measurement.
LETTER TO THE EDITOR
A New Method for Measuring Hemoglobin
Rangpur Medical College, Rangpur, Bangladesh
Received March 28, 2003; received in revised form April 3, 2003; accepted April 17, 2003
Laboratory Hematology 9:1-xx
© 2003 Carden Jennings Publishing Co.,Ltd.
Correspondence and reprint requests: Dr. Mujibur Rahman,MPhil,
Assistant Professor, Microbiology, Rangpur Medical College, Rangpur,
Bangladesh (e-mail: email@example.com).