And for my money, the best show in TV's greatest decade was Lost in Space. It's impossible to describe what watching this show was like in the 1960s. It's an experience that simply can't be re-produced today.
The reaction reaches its peak about 48 to 72 hours after the PPD is injected. Waiting too long or not long enough may cause an underestimation of the reaction and, therefore, affect how the test is read.A positive test will cause redness, itching and a raised, hardened area of skin called an induration.
Report Abuse. You should wait at least 12 days. I know this from experience. I had and hcg shot on june 28th and and iui done two days later. 12 days later i had a blood test done and it was positive. the blood test is suppose to be more accurate. if i were you i would wait at least 12 days. mcdaniel1205 Â· 8 years ago. Thumbs up. 0. Thumbs down.