Clsi Ep28 Now

“Reference intervals may need to be partitioned by age, sex, or other factors… especially for analytes like TSH, where values increase with age.”

Mrs. Park wasn’t abnormal. Aliyah’s reference population was just too young.

“That’s too narrow,” her senior technologist, Marcus, said, frowning at the scatter plot. “Manufacturer says 0.4 to 4.0. If we use ours, we’ll flag half our outpatients as abnormal.” clsi ep28

That night, Aliyah wrote a new lab policy. They would adopt the manufacturer’s broader interval for patients over 65—not out of laziness, but out of a deeper respect for EP28’s core principle: A reference interval is only as good as its reference population.

She called Mrs. Park’s family. The levothyroxine was stopped. The arrhythmia resolved. “Reference intervals may need to be partitioned by

Three weeks later, Mrs. Park was in the ER with atrial fibrillation—a known risk of overtreatment in the elderly.

The root cause analysis landed on Aliyah’s desk. She stared at the EP28 document, the same dog-eared copy she’d used for twenty years. And then she read the section she’d always skimmed: They would adopt the manufacturer’s broader interval for

Mrs. Eleanor Park, 68, came in for fatigue. Her TSH was 3.9 mIU/L—within the manufacturer’s range but above Aliyah’s verified upper limit of 3.2. Using the lab’s new narrow interval, the computer flagged it as Abnormal-High . The junior resident started her on low-dose levothyroxine.