PreOp Point-of-Care HbA1c Screening May Cut Complications

Point-of-care (POC) HbA1c measurements show a high level of agreement with central laboratory test in the outpatient setting, according to a small study published Jan. 18 in the Journal of Clinical Monitoring and Computing. Implementing broad preoperative screening may improve risk profiling in overweight and obese patients, who are prone to surgical cardiometabolic complications.

The authors say nondiabetic patients who are overweight are not routinely screened for metabolic abnormalities during their visit to the preoperative outpatient clinic. Yet, prior research has shown that impaired glucose tolerance or undiagnosed diabetes preoperatively is relatively common in patients undergoing surgery and may be associated with postoperative complications. POC HbA1c screening may enable implementation of broader preoperative screening, given that fasting is not necessary.

The researchers evaluated the level of agreement between a POC HbA1c test  (Siemens DCA Vantage HbA1c analyzer) and laboratory values in nondiabetic patients visiting the outpatient clinic for preoperative risk profiling (between November 2013 and February 2014) before elective surgery. POC HbA1c levels were measured in whole blood samples using a finger prick, as well as a venipuncture sample collected in the central laboratory on the same day.

Patients (n = 49) were 47 percent male and were a mean of 55 years old with a mean body mass index of 30.6 kg/m2. The mean HbA1c was 38.1mmol/mol or 5.6%. The authors report that the agreement between the POC HbA1c and the central laboratory values in nondiabetic, obese patients or patients who are overweight met the clinical standards for accuracy. One patient was diagnosed with an HbA1c of 6.7 %, indicative of diabetes. The percentage error was 9.2 percent for HbA1c expressed in mmol/mol and 5.9 percent for HbA1c in percent, both below the 10 percent threshold of acceptable deviation.

“We consider the use of the point-of-care HbA1c test valid and feasible to implement in the preoperative evaluation of patients scheduled for elective surgery,” write the authors led by Floris van Raalten, from Amsterdam University Medical Center in the Netherlands. “Our findings suggest that point-of-care HbA1c measurements might be valuable in identifying modifiable risk factors in patients undergoing surgery visiting the preoperative outpatient clinic, and may facilitate the promotion of preoperative prehabilitation and patient optimization programs by anesthetists.”

Takeaway: Given the potential risk for postoperative complications in patients with undiagnosed diabetes, and possibly impaired glucose control, broad screening using a POC HbA1c test during the preoperative anesthesia visit may be beneficial. POC HbA1c and central laboratory testing results are within acceptable agreement.