Aerospace Medicine Technical Reports
FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-12/5
Title and Subtitle: Effects of Fluid Load on Human Urine Characteristics Related to Workplace Drug Testing
Report Date: March 2012
Authors: Chaturvedi AK, Sershon JL, Craft KJ, Cardona PS, Soper JW, Canfield DV, Dubowski KM, Whinnery JE, Leyva MJ, Aston CE, Blevins SM, Wright JE, Fraser AD, Kuntz DJ
Abstract: During workplace drug testing, urine specimens are also tested for sample dilution, substitution, and adulteration. Often when urine sample validity testing indicates such sample modifications, donors argue that these irregularities are due to medical or health conditions, working conditions, dietary habits, or genetic differences.
There is a paucity of data correlating changes in urine characteristics after a fluid load to height, weight, body fat, and resting metabolic rate (RMR). In this study, 5 urine specimens from 12 males and 12 females were tested. These specimens were: 1 in the morning, 1 prior to drinking 800-mL of a beverage, and at 3 time intervals thereafter.
Beverages tested were water; a fully carbonated, carbohydrate-rich drink; a non-carbonated, electrolyte-rich drink; and a lightly carbonated drink. Of the 480 samples collected, 376 were in sufficient amounts for validity testing. Of these 376 samples, 36 (10%) had creatinine < 20 mg/dL but > 2 mg/dL; 27 (75%) of 36 had specific gravity < 1.0030 but > 1.0010. Thus, these 27 could be considered as dilute; 20 (74%) of 27 were obtained from females. For males with at least 1 dilute sample, body fat was 11% less and RMR was 29% more compared to males with no dilute samples (p > 0.05); for females with at least 1 dilute sample, height was 8% less and weight 20% less compared to females with no dilute samples (p > 0.05).
In general, individuals with a higher RMR appear to have a greater potential for producing dilute urine specimens than those with a lower RMR. Thus, a dilute sample does not necessarily indicate that it was intentionally diluted. Such samples must be carefully evaluated in consideration with recent liquid consumption of donors to avoid false accusations of intentionally providing a dilute urine sample.
Key Words: Forensic Science, Forensic Urine Drug Testing, Specimen Validity, Creatinine, Urine Specific Gravity, Body Mass Index, Resting Metabolic Rate
No. of Pages: 13
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-12/5
Title and Subtitle: Effects of Fluid Load on Human Urine Characteristics Related to Workplace Drug Testing
Report Date: March 2012
Authors: Chaturvedi AK, Sershon JL, Craft KJ, Cardona PS, Soper JW, Canfield DV, Dubowski KM, Whinnery JE, Leyva MJ, Aston CE, Blevins SM, Wright JE, Fraser AD, Kuntz DJ
Abstract: During workplace drug testing, urine specimens are also tested for sample dilution, substitution, and adulteration. Often when urine sample validity testing indicates such sample modifications, donors argue that these irregularities are due to medical or health conditions, working conditions, dietary habits, or genetic differences.
There is a paucity of data correlating changes in urine characteristics after a fluid load to height, weight, body fat, and resting metabolic rate (RMR). In this study, 5 urine specimens from 12 males and 12 females were tested. These specimens were: 1 in the morning, 1 prior to drinking 800-mL of a beverage, and at 3 time intervals thereafter.
Beverages tested were water; a fully carbonated, carbohydrate-rich drink; a non-carbonated, electrolyte-rich drink; and a lightly carbonated drink. Of the 480 samples collected, 376 were in sufficient amounts for validity testing. Of these 376 samples, 36 (10%) had creatinine < 20 mg/dL but > 2 mg/dL; 27 (75%) of 36 had specific gravity < 1.0030 but > 1.0010. Thus, these 27 could be considered as dilute; 20 (74%) of 27 were obtained from females. For males with at least 1 dilute sample, body fat was 11% less and RMR was 29% more compared to males with no dilute samples (p > 0.05); for females with at least 1 dilute sample, height was 8% less and weight 20% less compared to females with no dilute samples (p > 0.05).
In general, individuals with a higher RMR appear to have a greater potential for producing dilute urine specimens than those with a lower RMR. Thus, a dilute sample does not necessarily indicate that it was intentionally diluted. Such samples must be carefully evaluated in consideration with recent liquid consumption of donors to avoid false accusations of intentionally providing a dilute urine sample.
Key Words: Forensic Science, Forensic Urine Drug Testing, Specimen Validity, Creatinine, Urine Specific Gravity, Body Mass Index, Resting Metabolic Rate
No. of Pages: 13
Last updated: Thursday, May 31, 2012