Order entry errors can occur at any point in the ordering process, from the initial order made by the physician to a transcription error later down the road. Often, these errors are caused by a combination of a similarity of test names and a lack of technical knowledge within the ordering staff. In other words, two tests with that sounds alike get confused for each other.

One of the more common order entry errors that we see at Southeast Clinical Laboratories is a confusion between two derivatives of Vitamin D: 1,25-dihydroxy Vitamin D (1,25-OH₂ Vitamin D) and 25-hydroxy Vitamin D (25-OH Vitamin D). While the names of these two variants of Vitamin D are exceedingly similar, their clinical significance is anything but. One of these Vitamin D derivatives is among the most common laboratory tests we offer, routinely employed as part of an overall wellness check that you might see at an annual checkup. The other is a highly specialized test with complex considerations for interpretation and is reserved for investigating a narrow range of pathological conditions. Clearly, they are not interchangeable tests. And yet they are confused regularly.

The Vitamin D mix-up is a scenario in which staff continuing education may go a long way toward reducing laboratory error. If one is sensitive to the vastly different clinical contexts of these two seemingly similar versions of Vitamin D, then an order entry error is much less likely to be made. An exhaustive clinical understanding is not required—just the highlights should suffice.

25-OH Vitamin D: This is the more common of the Vitamin D tests. It is an inactive form of Vitamin D which is measured to assess the body’s stores of Vitamin D. 25-OH Vitamin D helps the provider understand the patient’s nutritional status with respect to Vitamin D, and if the value is too low, the provider might recommend Vitamin D supplements. Unmodified Vitamin D is rarely measured, so 25-OH Vitamin D is usually what is meant when a “Vitamin D” test is mentioned in ordinary contexts.

1,25-OH₂ Vitamin D: This is the less common Vitamin D test. It is the active form of Vitamin D which is measured to assess the body’s utilization of Vitamin D. The level of 1,25-OH₂ Vitamin D has no relationship to the body’s stores of Vitamin D but rather is regulated by parathyroid hormone (PTH). There are numerous pathological conditions in which 1,25-OH₂ Vitamin D is inappropriately elevated or decreased, including bone disease, kidney disease, and certain inflammatory conditions.

Continuing education is never-ending process which can benefit all members of the healthcare team. With the plethora of clinical laboratory tests available, it may be unrealistic to assume that all staff are fully knowledgeable about every test in the compendium. However, when mistakes are made in the clinical context (especially when made frequently), it is essential to identify the root causes and work to reduce their frequency and impact.