Method for improving usability and accuracy for physiological measurement

A method to improve placement of an adaptor to a mobile computing device to measure a test strip coupled to the adaptor with a camera and a screen on a face of the mobile computing device, the method comprising:

• determining whether a model of the mobile computing device is a first known model based on stored data accessible by the mobile computing device;
• in response to a determination that the model is not the first known model:
• guiding a user to generate a track from the camera to the screen;
• displaying a light area on a first portion of the screen based on the track;
• guiding the user to move the light area to a position on the screen aligned with the camera, wherein the light area and the camera are aligned with a key area of the test strip so that the camera is configured to capture an image of the key area;
• and
• guiding the user to place the adaptor to the mobile computing device according to the position of the light area on the screen.