Table 3.

Guidance for Selecting Environmental Laboratory Tests

1. Take an environmental history to determine if the health problem or symptom of concern may be related to an environmental exposure (Table 2).

2.Characterize the potential exposure(s) of concern:

• Is there a completed route of exposure? (opportunity for internal dose through inhalation, ingestion, or dermal absorption)  • Did the potential exposure occur before the health problem or symptom appeared?  • How long did the exposure last? Continuous or intermittent?  • What are evidence-based health effects associated with the toxicant?

3. Characterize the symptoms in relation to potential exposure(s):

• Do symptoms improve or worsen at a particular time? In a particular location?  • Do symptoms worsen during a particular activity?  • Are household members experiencing similar symptoms?

4. Determine if validated laboratory tests are available that will help to accurately document the exposure (may require input from environmental or toxicology specialists: www.pehsu.net).

• Will the laboratory measurements correlate with toxic effects?  • Will the results influence patient management?  • Is a certified laboratory available to analyze the specimen?  • What is the proper specimen for the exposure? (e.g., blood versus urine)  • Are there reliable and clinically-relevant reference ranges?

5. Consider the appropriate next steps for patient:

• May involve targeted environmental tests, or referrals to specialists (e.g., allergist)  • Referral to PEHSU network or other appropriate resource as needed for advice on diagnosis, management, or prevention of environmental concern  • Routine management of symptoms, as directed by history and physical exam

6. Provide strategies to reduce exposures of concern. This is desirable, even in absence of laboratory testing (www.nyscheck.org/rx; peht.ucsf.edu).