During my early years as a pediatric hospitalist in the U.K. during the ’80s, a figure that loomed large was the chemical pathologist (CP).
The CP was the guardian of the laboratory, and every hospital had one. This fearsome beast was approached with trepidation, as the outcome was likely to be a unique but bruising “educational experience.”

Interaction was common because almost every lab test apart from the CBC, ESR, chem 20, and TSH had to be approved by the CP. Of course, this sounds ludicrous today, but this was a long time ago!

As a junior doctor rounding with the attending, the latter might decide that the serum porcelain level should be measured. I would complete the pathology request form (paper in those days) and send it to the lab. I would then brace myself for the call.

“You want WHAT? What the hell for? Do you know how much that test costs? You know the plasma has to be kept at minus 20 degrees and shipped to the reference lab that way? Convince me that the patient really needs this test!”

I would plead my case as best I could.

“This is entirely the wrong test for this patient. It won’t help at all. You’re an idiot, Dr. Young. You need the serum tin-tack level, not porcelain!”

You see, the CP was the Keeper of the Knowledge of Tests and their use. He/she stopped unnecessary ones from being performed; something of importance in a health care system like Britain’s National Health Service where costs matter. Discussing the patient’s case prior to any testing was often very helpful as he/she could suggest a way to proceed diagnostically. Once you had received your berating, you would get an education regarding the test and the patient’s likely diagnosis. When the result of the now-appropriate test came back, the CP would help you interpret it.

The CP would also review any abnormal test result generated by his/her lab and write a helpful comment on the (paper) report. For example, if a child’s CBC shows anemia, the CP might write “hypochromic microcytic anemia, iron deficiency most likely. Recommend ferritin level. If this is normal, consider thalassemia.”

When I did my fellowship in the U.S. in 1989, I was staggered by the ease with which fancy diagnostic tests could be ordered with never any resistance or blowback from the lab, but no education either. The same goes for radiology.

Much of my practice as a pediatric endocrinologist has involved patients who underwent tests that were never strictly indicated, or results that have been misinterpreted. For example, the majority of children referred to me with “abnormal” TFTs do not have any thyroid dysfunction or disease.

Today, how can we get a CP’s benefits without having one?

The first step would be improving how tests are reported. Whether paper or electronic, they are often poorly designed and hard to interpret. Labs need to report in a user-friendly format and clearly mark abnormal values.

Secondly, for heaven’s sake, please put the reference range appropriate for the age, sex, and race. If the patient is under 18 and the test is influenced by pubertal status (e.g., estrogen), then say so or, even better, put ranges by Tanner staging. In my experience, much harm results from failing to do this.

Lab directors should take a look at radiologist’s reports. They don’t just list any abnormality seen but typically give a differential diagnosis and suggest appropriate further imaging. Path reports could do the same. It would not be difficult to construct programs that added helpful interpretive information, much like the child with anemia above.

As an example, I have been referred to many children with an isolated (and unexpectedly) raised alkaline phosphatase, typically as suspected rickets. Yet most had “hyperphosphatasemia,” a benign, typically transient condition with the enzyme level in the thousands. A comment on the report that this was the most likely diagnosis would have saved the child a trip to me. Surely software could be developed to act in this way. A value of say, above 500, could trigger the comment.

One aid in interpreting lab results is the various handbooks available specifically for this, though many seem to be written for nurses and, therefore, are a little less technical. I have always kept one on my shelf.

Another resource is Labcorp’s test directory, easily accessed online at their website. A short but useful monograph accompanies most of the tests. For example, the one for alkaline phosphatase discusses causes of both low and high values (including transient hyperphosphatasemia).

When it comes to help with selecting the right test to order in the first place, diagnostic algorithms are a good place to start. Free sources include the Mayo Clinic lab website, which has an extensive menu of diseases and conditions, as does the American Family Physician’s website. If you’re willing to pay, $120 will get you a year’s subscription to the 5MinuteConsult online site. If you prefer books, then the 5 Minute Clinical Consult manual is a good choice. (I have no financial interest in either.)

Still, nothing beats speaking in person with a CP. And, hiding in the national labs, we find the successors to the CP’s of old. Many labs offer the opportunity to speak with “consultants/specialists” who will help in selecting the right test and give guidance. Quest Diagnostics offers you the opportunity to talk to over 600 MDs/PhDs and 40 or so geneticists.

The moral of this little essay is simple. Before ordering a test you are unfamiliar with, consider searching out a diagnostic algorithm. If it is something esoteric, consider talking to one of these consultant experts. If you get a path report with an abnormal result, give a moment’s thought to whether the lab used the appropriate normal range. Look up the test so you fully understand its significance and can make a sensible next move.

Oh, and a final word about the consultants. I have used their services on occasion, and here’s the good news: not one of them said to me, “Dr. Young, you’re an idiot.”

Martin C. Young is a pediatric endocrinologist.