The 2003 Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines recommended maintaining PTH values below 300 pg/mL (three to five times the upper limit), whereas the 2009 KDIGO guidelines recommended PTH levels between two and nine times the upper limit (up to 746 pg/mL; grade 2C recommendation) 11,12; however, little evidence is available to support these (changes in) guidelines. The gene discussed is PTH; the disease is kidney disorder.