So, basically, withholding information is not the same thing as lying, but depending on the situation, you will have to decide whether it is better to withhold the information or not.
HCH may refer to: Hampton Court House, an independent school in Surrey, UK. Hexachlorocyclohexane, a group of chemical compounds. Holmes Chapel railway station (National Rail station code), in Cheshire, England.
MCH stands for mean corpuscular hemoglobin in hematology. Corpuscles are red and white blood cells. Hemoglobin is the oxygen-carrying pigment in red blood cells. Mean refers to the average weight of hemoglobin per red blood cell. High MCH means more hemoglobin than normal for a person's age and gender, which -- counterintuitively -- can indicate a particular type of anemia.