Google Answers Logo
View Question
Q: Forensics - False Positives ( Answered 5 out of 5 stars,   0 Comments )
Subject: Forensics - False Positives
Category: Science > Chemistry
Asked by: bjbrooks-ga
List Price: $5.00
Posted: 15 Dec 2005 12:22 PST
Expires: 14 Jan 2006 12:22 PST
Question ID: 606264
What are some common substances that might give a false positive when
given a luminol blood test, such as soft drinks, saliva, weeds, etc?

Request for Question Clarification by pinkfreud-ga on 15 Dec 2005 12:27 PST
Here you'll find a long list of substances that can cause false
positives with Luminol (and also with Hemaglow):

If this list is fully satisfactory, I'll be glad to repost it as your
official answer. If this isn't what you need, a few more details would
be helpful.

Clarification of Question by bjbrooks-ga on 15 Dec 2005 12:57 PST
That will work.. Thanks!
Subject: Re: Forensics - False Positives
Answered By: pinkfreud-ga on 15 Dec 2005 13:15 PST
Rated:5 out of 5 stars
I'm glad to have been able to help you find what you needed.

As I mentioned above, there's a list here of substances that are known
to cause false positives with Luminol:
Lightning Powder Company: Technical Note

This appears to be the most detailed list of such substances that is
available for free on the Web. If you need additional detail, you may
want to consider purchasing a copy of this research article, "A study
of common interferences with the forensic luminol test for blood":

"A wide range of domestic and industrial substances that might be
mistaken for haemoglobin in the forensic luminol test for blood were
examined. The substances studied were in the categories of vegetable
or fruit pulps and juices; domestic and commercial oils; cleaning
agents; an insecticide; and various glues, paints and varnishes. A
significant number of substances in each category gave luminescence
intensities that were comparable with the intensities of undiluted
haemoglobin, when sprayed with the standard forensic solution
containing aqueous alkaline luminol and sodium perborate. In these
cases the substance could be easily mistaken for blood when the
luminol test is used, but in the remaining cases the luminescence
intensity was so weak that it is unlikely that a false-positive test
would be obtained. In a few cases the brightly emitting substance
could be distinguished from blood by a small but detectable shift of
the peak emission wavelength. The results indicated that particular
care should be taken to avoid interferences when a crime scene is
contaminated with parsnip, turnip or horseradish, and when surfaces
coated with enamel paint are involved. To a lesser extent, some care
should be taken when surfaces covered with terracotta or ceramic
tiles, polyurethane varnishes or jute and sisal matting are involved."

Wiley InterScience: Luminescence

My Google search strategy:

Google Web Search: forensic luminol "false positive"

Best regards,
bjbrooks-ga rated this answer:5 out of 5 stars
Thanks again!

There are no comments at this time.

Important Disclaimer: Answers and comments provided on Google Answers are general information, and are not intended to substitute for informed professional medical, psychiatric, psychological, tax, legal, investment, accounting, or other professional advice. Google does not endorse, and expressly disclaims liability for any product, manufacturer, distributor, service or service provider mentioned or any opinion expressed in answers or comments. Please read carefully the Google Answers Terms of Service.

If you feel that you have found inappropriate content, please let us know by emailing us at with the question ID listed above. Thank you.
Search Google Answers for
Google Answers  

Google Home - Answers FAQ - Terms of Service - Privacy Policy