296 VI. HEMOGLOBIN 



cases in which the content of hem/globin and sulfhemoglobin cannot be 

 neglected; these have recently increased in frequency due to the widespread 

 use of sulfonamides and, in x^ustraha, of phenacetin. In adopting a simple 

 procedure of hemoglobin estimation to be recommended for general use, it 

 must first be decided which of the above-mentioned pigments should be 

 included under the term "hemoglobin." 



The Medical Research Counc 1 Report of 1943 {1893) recommends as ideal 

 methods which determine the sum of all the hemoglobin derivatives. In our 

 opinion this is unjustified. Physiologically, the pigments fall into three 

 classes: {1) Pigments able to function as oxygen carriers: hemoglobin, 

 oxyhemoglobin. {2) Pigments unable to function, but reconvertible into 

 functional hemoglobin: hemoglobin, carboxyhemoglobin. {3) Pigments 

 unable to function, and not reconvertible to hemoglobins: sulfhemoglobin, 

 choleglobin. 



Obviously the third class should not be included in clinical hemoglobin 

 analysis. According to whether the lack of hemoglobin is chronic or acute, 

 the ideal method should give the sum of the pigments in the first two classes 

 or of the first class only. 



None of the methods in common use to-day fulfills either of these conditions 

 and should therefore not be applied in cases in which the presence of much 

 sulfhemoglobin is suspected without additional estimation of sulfhemoglobin. 

 In describing various methods of hemoglobin estimation, we shall indicate 

 which of the various hemoglobin derivatives are measured by the method in 

 question. 



9.1.2. Errors of Technique and Standardization. This lack of 

 specificity is, however, only a minor weakness in hemoglobinometry; 

 other defects are far more serious. In order of importance these are : 

 the use of wrongly standardized instruments, incorrect sampling, lack 

 of care for the instruments by poorly trained (though equally poorly 

 paid) workers, failure to adhere to specified conditions {e.g., with 

 regard to illumination or timing), and, only in the last resort, the 

 application of less exact methods. 



A few examples may suffice: The fact that the acid hematin method has 

 a variation of ± 5% is of small significance, if individual hemoglobinometers 

 vary ± 30% in their standardization, if the pipets used for sampling are 

 wrongly calibrated, the instrument dirty, the illumination varied from day- 

 light to artificial light and if the prescribed timing is neglected. The fact 

 that an error of 1 g. hemoglobin per 100 ml. blood (7%) in the standardization 

 of British Haldane hemoglobinometers remained undetected for decades 

 {1537,1811) is a sad reflection on the state of clinical hemoglobinometry. 

 This now explains why the "normal" English values were always far below 

 those observed in the I'^nited States, Australia, and Germany. 



The latter example emphasizes also the need for abandonment of the 

 outmoded hemoglobin percentage scale. There is no unanimity on what 



