Hello Sarah! Thank you for appreciating the video. The Hemoglobin standard mentioned is a commercially prepared standard that is included in a kit for Hemoglobin determination. :) The kit may also include the Drabkin's reagent used for the assay. :)

Hello there! :) Thanks for watching the video. The amount of blood (20uL) that was used in the experiment was based on the procedure found in Rodak's Hematology which is our Reference book for Hematology. It was mentioned that a 1:251 dilution should be made and that will be achieved by diluting 20uL blood with 5mL reagent. This large dilution, as literature suggests, will help eliminate problems of turbidity caused by lipids, proteins, and other cellular matter that may interfere with spectrophotometric estimation. Another reference book that used 20uL blood and 5mL reagent is Hematology by Barbara Brown. Some Cyanmethemoglobin kits also use this dilution. As for the next concern about the blood being diluted, this is addressed by the determination of a standard Hemoglobin and the computation that involves the concentration of the standard and sample from the spectrophotometer. If the computation will not be used, another method is to use a Hemoglobin Standard curve that involves several dilutions of a commercially available standard. Hope this helps. :)