H and H, often abbreviated as "H&H," refers to two essential and frequently conducted blood tests: hemoglobin and hematocrit. Hemoglobin, a protein pigment responsible for transporting oxygen in the blood, is found in red blood cells. In hemoglobin testing (Hb), the level is typically reported as the total hemoglobin in grams per deciliter (gm/dl) of whole blood, with a deciliter equating to 100 milliliters. Normal hemoglobin ranges vary based on age and gender from adolescence onward:- Newborns: 17-22 gm/dl- One week old: 15-20 gm/dl- One month old: 11-15 gm/dl- Children: 11-13 gm/dl- Adult males: 14-18 gm/dl- Adult females: 12-16 gm/dl- Men past middle age: 12.4-14.9 gm/dl- Women past middle age: 11.7-13.8 gm/dlThese values might slightly differ between laboratories, and some labs do not distinguish between adult and post-middle age hemoglobin levels.Hematocrit represents the volume percentage of blood composed of red blood cells. This is expressed as a percentage; for instance, a hematocrit of 25% indicates that 25 milliliters of red blood cells are present in 100 milliliters of blood, meaning a quarter of the blood consists of red cells. Hematocrit normal ranges also depend on age and gender after adolescence:- Newborns: 55-68%- One week old: 47-65%- One month old: 37-49%- Three months old: 30-36%- One year old: 29-41%- Ten years old: 36-40%- Adult males: 42-54%- Adult females: 38-46%As with hemoglobin, these values can vary slightly between different laboratories.

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