Laboratory reference intervals influence referral patterns for hemoglobin abnormalities in the Ontario virtual care...

Area of Science:

• Clinical laboratory science
• Health informatics
• Internal medicine

Background:

• Electronic consultation (eConsult) platforms facilitate specialist referrals.
• Laboratory reference intervals can vary, potentially affecting clinical decisions.
• Anemia and elevated hemoglobin require accurate diagnostic evaluation.

Purpose of the Study:

• To assess how laboratory-specific hemoglobin reference intervals influence eConsult referral patterns for suspected anemia and elevated hemoglobin.
• To evaluate the extent of pre-referral laboratory testing in these eConsults.
• To identify opportunities for optimizing the referral process.

Main Methods:

• Retrospective cross-sectional study of eConsults for hemoglobin abnormalities via the Ontario Telemedicine Network.
• Analysis of referrals from July 2019 to June 2023 at a tertiary care center.
• Comparison of referral patterns based on varying laboratory hemoglobin thresholds and review of pre-referral test data.

Main Results:

• Significant variance in referral patterns was observed based on different laboratory hemoglobin thresholds.
• Referrals for suspected anemia in females were associated with higher hemoglobin concentrations when using higher laboratory lower limits (≥120 g/L).
• Pre-referral testing was frequently incomplete, with missing ferritin (44%), B12 (53%), and reticulocyte count (81%) data.

Conclusions:

• Laboratory reference intervals for hemoglobin substantially impact referral patterns within Ontario's eConsult system.
• Standardization of reference intervals and comprehensive pre-referral testing are needed to reduce unnecessary medicalization and referrals.
• An anemia management algorithm is proposed to guide primary care providers in pre-referral investigations.