Table 1.

Current ranges of urinary total [U] and U isotopic ratios that identify DU estimated from different levels of DU inhalation exposure during the 1991 Gulf War, time since exposure, and daily dietary intake of natural uranium running up to urine sample collection.

Parameters specified in the prediction model			Ranges of parameters expected 18 years after specified DU inhalation exposure			Can expected levels of DU be detected by criteria used in prior studies?
Standard DU exposure level	Estimated DU intake (mg) for the exposure level in 1991 Gulf Wara	Daily dietary U excretion (ng) in run-up to testing	Total [U] (ng U/g creatinine)	238U/235U	236U/238U × 10–6	Method 1: total [U] > 50 ng U/g creatinineb	Method 2: 238U/235U > 166 by SF-ICP-MSc	Method 3: 238U/235U > 140 by MC-ICP-MSd
Level I	250	2	14.5–74.5	367–467	25.9–29.2	Rarely	Yes	Yes
		8	20.5–80.5	247–397	18.3–27.0	Rarely	Yes	Yes
Level II	10	2	2.5–4.9	161–241	6.0–17.8	No	Yes	Yes
		8	8.5–10.9	144–171	1.8–8.0	No	No	Yes
Level II	5	2	2.3–3.5	150–198	3.3–12.6	No	No	Yes
		8	8.3–9.5	141–155	0.9 -4.6	No	No	Yes
Level III	2	2	2.1–2.6	143–165	1.4–6.7	No	No	Yes
		8	8.1–8.6	139–145	0.4–2.0	No	No	Yes

^aNumerical values are derived from calculations of^8,23,24 as illustrated in Fig. 1, described in more detail in on-line methods.

^bIn the most recent study of DU in Gulf War veterans, Dorsey et al.²⁰ screened urine total [U] for DU by this criterion.

^cDorsey et al.²⁰ identified the presence of DU with the ²³⁸U/²³⁵U ratio measured by lower precision sector field–inductively coupled plasma-mass spectrometry (SF-ICP-MS).

^dThe present study identified the presence of DU with the ²³⁸U/²³⁵U ratio measured by the high precision multiple collector–inductively coupled plasma-mass spectrometry (MC-ICP-MS).