Employees who participated in medical surveillance programs up until recently were overwhelmingly male. That has changed in recent years and nearly every employer now has both male and female employees who are required to participate in annual medical surveillance requirements. Yet, here has been no medical surveillance program design, testing requirements or interpretation of findings based on gender. Well, that may be changing very soon…
Recently, Corporate Wellness identified a pattern of abnormal laboratory findings in female employees who completed serum cholinesterase screens as baseline tests for a new environmental consulting client. They have more female employees than many others in the industry. While the laboratory normal range for this test is 1900 to 3800 units per milliliter (U/mL), more than half of the female employees we tested this year had significantly lower results – some hovering around the 1000 U/mL mark even after retesting. Normally, we’d recommend limited potential for exposure and retest for 75% of normal and removal from all assignments that might include exposures for findings that are 60% of normal or below.
Together with Dr. Randy Young who heads clinical operations for LabCorp, we took a closer look. We found that although there is currently only a single normal range for both males and females, normal findings for females, and especially females using estrogen based birth control, are more likely to be in the 1000 to 1800 units range – well below the published “normals” of 1800- to 3800 units.
LabCorp examined its own results, for our clients’ employees and their entire patient population and found that our observations appear to be correct. And they will be publishing a new set of “normals” for both serum and rbc cholinesterase that are gender based.
For the moment, we are sending letters to all female employees whose laboratory results are below 1800 units, explaining where we are in the process of helping set new gender based normals but also offering retest if they’d like it.
We suspect that this may be the first of many things we learn as a result of the changing workforce.