Criteria of cysts in USG to diagnose ADPKD at 40years of age

Diagnosis OF ADPKD: Diagnosis is typically made from a positive family history consistent with autosomal dominant inheritance and multiple kidney cysts bilaterally. Renal ultrasonography is often used for presymptomatic screening of at-risk subjects and for evaluation of potential living related kidney donors from ADPKD families. The presence of at least two renal cysts (unilateral or bilateral) is sufficient for diagnosis among at-risk subjects between 15 and 29 years of age with a sensitivity of 96% and specificity of 100%. The presence of at least two cysts in each kidney and the presence at least four cysts in each kidney are required for the diagnosis of at-risk subjects age 30 to 59 years and age 60 years or older, respectively, with a sensitivity of 100% and specificity of 100%. This is because there is an increased frequency of developing simple renal cysts with age.Reference: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 339; Polycystic Kidney Disease and Other Inherited Disorders of tubule growth and Development