How long will nicotine show up in cotinine ql serum blood test?

I found this - Trace amounts of nicotine can be detected in blood and urine for several hours, but they should be gone by 48 hours. However, if you are being tested for nicotine, there is a metabolite of nicotine, called cotinine, which can be detected in blood or urine for as long as 7 to 10 days after your last exposure to nicotine.