Coverage Value: Standardizing the Scientific Criteria for Determining Coverage
The Coverage Value calculation was developed by Dr. Koray Erdogan as an objective method to standardize scientific criteria for calculating coverage through two components; density and thickness. This criteria addresses not only overall coverage, but also creates a standard for avoiding donor depletion, an issue that has been an area of trepidation to hair transplant surgeons for some time and especially where higher graft counts are concerned. Since the two items of greatest concern to both the patient and surgeon is donor capacity and good coverage, this is the main objective of the Coverage Value Calculation.
The Calculation
Coverage Value is calculated by multiplying hair density—the number of hairs per square centimetre—by average hair thickness. Dr. Koray Erdoğan assesses the donor regions of the scalp (occipital, parietal and temporal, at the back and sides) separately and determines the total number of grafts that can be extracted from these regions according to the Coverage Value calculation. When planning the amount and distribution of extraction, Dr. Erdoğan also interprets the regional values alongside hair texture, hair-to-skin contrast and the natural angle of the hair.
With the assistance of various tools, and especially the recently developed KE-Bot robotic scanning system, the Coverage Value calculation achieves very high levels of accuracy. These measurements inform an individual treatment plan. This preserves the density and natural appearance of the donor hair while retaining the reserve that may be needed for future procedures.
Published Explanation
The method is described in the textbook chapter “The Coverage Value Calculation: An Objective Method of Evaluating Donor Supply and Coverage” in Hair Transplantation, sixth edition.
To discuss your donor area and the coverage you would like to achieve, complete the online consultation form with the requested photographs and background information.
