On 1st day, patient's BP is measured by a doctor, which is 130/80 mm of Hg. After 3 days, pt is again brought to the hospital while another doctor is on duty. Pt is under same physical & emotional state as 3 days ago. Now B.P is measured which is 150/97. Which of the following explains this reading ?

3 errors are normally seen in measuring B.P: 1. Subject errors : Reading is disturbed d/t fear/any emotional stress of the patient. 2. Observer errors : Due to difference in interpreting koratkoff's sounds & hearing power of different doctors 3. Instrumental error : Due to any problem in B.P apparatus resulting in false reading. - In the given question, as patient's physical & emotional state is the same, subject bias is unlikely to occur - As two doctors took the reading at two different times, it point towards observer error as there would be differences b/w their hearing acuity & interpreting sounds.