Scales are a necessary piece of equipment for all medical facilities. These silent workhorses sit in the hallways and corners of every medical office and every hospital department, and they are used by nearly every patient as part of their intake and daily care.

A patient’s weight is vital information for detecting fluid retention, calculating proper medication dosages and screening for malnutrition. Yet, heathcare professionals sometimes overlook the importance of accuracy and safety, methodically recording readings without a second thought. Outdated, unsafe scales can lead to falls and injuries for both patients and healthcare professionals. Improperly calibrated or inaccurate scales can lead to incorrect treatment or inconsistencies across a health system. In fact, recent studies show that many medical scales are troublingly inaccurate. It’s time to weigh the risks posed by your physician and hospital customers’ scales and take steps to protect their patients, their employees and their bottom line.

Higher weights, lower accuracy
As the obesity epidemic grows, medical professionals are seeing heavier patients. According to the National Council on Strength and Fitness, 3.8 million Americans weigh over 300 pounds, and 400,000 weigh more than 400 pounds.1 Many scales have high capacities, but they are not accurate at higher weights. As a patient’s weight increases, the accuracy of many scales decreases. The results can mean inconsistent readings, leading to an inaccurate representation of a patient’s weight over time. Healthcare standards recommend that scales be precise to 1 pound per 150 pounds of weight to ensure accurate dosing and treatment. However, a recent study of scales in Kansas City-area health facilities found average inaccuracies ranging from 1.3 pounds at 100 pounds of weight, to 3.8 pounds at 250 pounds of weight. As the test weights increase, more scales were found to be inaccurate. When tested at 200 pounds, the study found that 15.1 percent of scales were off by more than 6 pounds – or one Body Mass Index (BMI) unit. At 250 pounds, the percentage of inaccurate scales increased to 20.8 percent. Since many physicians use a patient’s BMI as a critical measure for planning treatment and care options, this inaccuracy can lead to over- and under-treatment, denial of proper treatment or ill-informed guidance.2

3.8 million Americans today weigh over 300 pounds.
400,000 Americans weigh more than 400 pounds.

The risks — and cost — of inaccuracy can be substantial. For a patient undergoing treatment, inaccuracy can mask a weight gain or loss that signals health changes. According to a study by Nursing, a heart patient with a weight variance as small as 3 pounds requires assessments for peripheral edema jugular venous distension, dyspnea or abnormal lung sounds. Similarly, patients with renal failure or some cancers typically receive medication doses based on their current weight.3 To ensure accuracy across a variety of patient weights, scales should be calibrated regularly, particularly because in the course of daily usage, scales are bumped or jarred, which can affect their accuracy.

A study by the UK’s National Health Services found that 22 percent of scales were not set to zero, and a third of all scales tested were inaccurate. The study, which examined 7,875 scales at more than 200 hospitals, noted that while small inaccuracies may not be important when monitoring obese adults, inaccurately weighing oncology patients, children or infants to determine medication doses could be dangerous.4 For instance, the Pennsylvania Patient Safety Authority surveyed four years of state health event reports and found 479 instances of medication errors stemming from inaccurate patient weight. Of these incidents, 67 percent resulted in a patient receiving an incorrect dose, with 1.3 percent of cases causing enough harm to warrant additional treatment.5

According to the Pennsylvania Patient Safety Authority, in one state:

  • 479 medication errors were caused by inaccurate patient weight.
  • 67 percent of these incidents resulted in a patient receiving an incorrect dose.

Standardization matters
Many hospital systems or IDNs have not made scale standardization a priority, with most systems using four or more scale brands throughout their organization’s facilities. This requires staff to be familiar with multiple scales’ operation and can lead to variances in the weight results. Standardization across a hospital system or network benefits both patients and staff. By using standard scales and calibration procedures, a patient’s weight variation across several locations within the network becomes more meaningful. With newer scales that integrate with a facility’s electronic medical record system, weight readings are automatically added to a patient’s record, reducing the risk of transcription error on date or weight. Additionally, staff working in multiple locations across a hospital system can apply the same best practices when using standardized equipment. Overall, standardizing across the continuum of care helps staff provide a consistently high level of patient care while reducing costs to an organization.

Next steps
Your hospital customers can start by taking an inventory of every scale in their facility or network.

  • How many are there?
  • Where are they located?
  • Who’s using them, and how often?

Do they have rail supports or low platforms, particularly in departments that see more elderly and frail patients?
Next, hospitals and IDNs should evaluate accuracy across the entire range of use. They should verify when they were last calibrated, their maximum accurate weight and how often they are calibrated. Is someone at the IDN responsible for calibrating scales, and are users trained to zero them out between patients? Particularly in larger facilities or IDNs, responsibility for scales can be centralized. They should develop standards for usage and establish maintenance procedures and schedules to help ensure that accuracy does not lapse. Then, they should train staff to use the scales properly and empower them to point out when something doesn’t seem right. The patients’ health — and the provider’s bottom line — depends on it.

Published:  The Journal of Healthcare Contracting