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Watering down the truth: What to do about dilute urine drug tests

Richard Donze, DO, MPH
Vice President, Medical Affairs, Chester County Hospital
Medical Director, The Occupational Health Center

As I write in late March looking outside at the new maple tree buds, I recall a time years ago when I trudged through early spring mud in the Vermont sugarbush to collect the gushing sap that would later boil down to that wonderfully unique New World food-maple syrup. It's all part of that literal and figurative recurring tale about the end of winter, the renewal of the earth, the return of spring and all the "sweetness" it can bring. And, of course, whenever I recall maple sap, I think about dilute urine drug tests. The reason, in case it isn't obvious, is that dilute urine is a lot like maple sap-it's hard to tell what might be in there because of all the water.

Maple syrup and maple sugar are very concentrated distillates of a sap that is about 98% water. It takes about 40 gallons of sap to produces one gallon of syrup after boiling down over an outdoor open fire (the old-fashioned way I did it) or more modern evaporation methods. Bearded, flannel-shirted, woodsmoke-squinting maple sugaring experts tell me they can detect the faintest sweetness in the very dilute sap, but I never could; to me, it mostly tastes like what it mostly looks like-water. I know the sugar is in there because I've watched the steaming clear liquid turn brown in that magic, alchemical instant; but at the start of the process-tapping the tree, carrying the buckets, splitting the wood and finally lighting the fire-it's an act of faith.

Trying to get my tongue to pick up characteristic maple sweetness in very dilute sap is like trying to detect unauthorized drugs in very dilute urine-it just may not register, even on the very sophisticated equipment of a DHHS-certified lab, or the level isn't high enough to meet the "positive" threshold. And despite the creative and ever-proliferating industry that offers to help the weed-puffing coke-blowing horse-shooting worker beat the urine test, one of the simplest and most effective ways to accomplish this is internal dilution, a.k.a. drinking tons of water.

The problem is that urine deliberately diluted to beat a drug test is indistinguishable from urine inadvertently diluted by those doctor-recommended eight daily glasses of watery whatever to achieve good health. The latter behavior is so common now I suspect we will never lose our unnecessary pinkies as some evolutionary theorists have predicted, and instead maybe we'll grow water-bottle-hands (I thank the Almighty every day that my boyhood friends and I survived the perils of childhood dehydration because, unlike today's electrolyte-replenishing-sports-drink-toting youth, when we played outside every summer afternoon and sweat so much we could taste the crystallized salt when licking dry lips, we only went once or twice the whole day to suck a little refreshment out of some neighbor's garden hose). Dilution, regardless of method, yields the same result; so until we discover a reliable way to test intent, we are left with versions of the truth that can be, at times, pretty watered-down.

So what do you do when the Medical Review Officer (MRO) interpreting the drug screen tells you the test is negative, but also dilute? The answer depends on whether your drug tests are so-called "regulated" or not; that is, whether or not you test as part of a Federal mandate (most commonly the Department of Transportation, or DOT) or internal, company-initiated policy.

Under the DOT, the most dilute urines (as determined by two urine measurements called specific gravity and creatinine) require an immediate re-collection under direct observation; for urine that is less dilute, sending the person back is discretionary, but you must treat donors the same within a test category (e.g., all tests done pre-employment or for reasonable suspicion might get repeat collections, but not randoms, or vice versa, etc.). Don't worry about memorizing
the specific numbers; your MRO will tell you when to do what.

If you don't come under the DOT's rules, you can do what you want;however, many companies follow the DOT's lead whether they need to or not,since the federal regulations are the only recognized external standards. Even though your decisions are still your own and may be defensible, it's hard to challenge any action you take that is consistent with what the Feds require. We use the DOT's precedent when advising companies on policy decisions; when they ask whether we recommend repeat collections on the urines that are only slightly dilute, our usual advice is to let them go, based on an assumption that most of these are probably cases of innocent, inadvertent dilution by people drinking more for good health or to be sure they don't develop "shy bladders" when given the cup and asked to produce a specimen.

It's a business decision, but some would say that the added expense of a repeat test isn't justified by the yield of positives, plus the prediction that most times these donors are solid citizens who feel adequate hydration is essential to good health. Certainly I've seen cases of donors who may have assumed they had dodged the bullet after the first test only to get caught on the second (thought it was safe to "party," perhaps), but these are the exceptions. The opposite argument is that a repeat drug screen is reasonable, doesn't cost too much, and enables you to pick up a couple of tricksters here and there that would have otherwise gone undetected; plus, a policy to re-test doesn't mean
the game goes on forever, since even the DOT says you have to stop after two dilutes in a row.

It's important to remember that your mission is to take reasonable steps to ensure a drug-free workplace, and not to identify and apprehend anyone you can find using controlled substances without proper authorization. You're not the
federal Drug Enforcement Administration. Workplace drug testing was originally conceived as a deterrent, based on the notion that just having a program would discourage some users from using, at least long enough to pass the test (although it's still astounding how many people fail pre-employment drug testing, even though they can "study" for these tests). Add a random testing program and with it the idea that on any given day someone's name may be called
(even if they were just called, since everyone in the pool is eligible every time a selection is made), and any value of deterrence increases. And finally, if you have to or want to send back the dilute testers for one more shot based on the
act of faith that something may have been in that watered-down first specimen, you will surprise a few folks who haven't had enough time to turn their drug-rich syrup into something more sap-like.

If you want to preserve your mental health, though, resign yourself to the reality that some determined users will beat the test. It's unavoidable. They will use sophisticated adulterants purchased online, or something as simple and basic as drinking extra water. If you accept this, it doesn't mean you are shirking your responsibility to protect capital investments, bottom line, other workers and public safety. You're just doing what you can. You may think yourself a sap for letting yourself get fooled, or the employee a sap for ever trying to fool you, but don't go there. Look outside instead, and recognize that the real sap is sweet watery nectar that rises in trees and allows spring to come.

Last Updated: 6/1/2012