Appropriate Action for Delta Flag in Hemoglobin Results
The most appropriate action when a patient's hemoglobin increases from 7.8 g/dL to 10.5 g/dL within 12 hours is to check if the patient recently received blood transfusions (Option C). This significant increase of 2.7 g/dL in such a short timeframe is most likely explained by recent transfusion rather than physiological improvement.
Understanding Delta Flags in Laboratory Results
Delta flags are triggered when there is a significant change in a laboratory value compared to previous results. For hemoglobin, a 2.7 g/dL increase in 12 hours exceeds typical physiological improvement rates and warrants investigation.
Why Check for Transfusions?
Magnitude of change: A single unit of packed red blood cells typically increases hemoglobin by approximately 1 g/dL in an average-sized adult 1. The observed 2.7 g/dL increase suggests multiple units were likely transfused.
Timeframe: The 12-hour window is consistent with the timing of transfusion effects, as transfused blood immediately increases hemoglobin levels 1.
Starting hemoglobin level: The initial value of 7.8 g/dL is below recommended transfusion thresholds for many patient populations, making transfusion a likely clinical intervention 1.
Why Other Options Are Inappropriate
Option A (Report the CBC results, the patient is obviously improving): This assumes natural improvement, which is physiologically implausible at this rate. No patient "naturally" improves hemoglobin by 2.7 g/dL in 12 hours without intervention.
Option B (Check for clots): While clots in specimens can affect some laboratory parameters, they typically cause falsely low rather than falsely high hemoglobin readings.
Option D (Report all results except hemoglobin): Rejecting the hemoglobin result without investigation would delay reporting of potentially valid results and could impact patient care.
Clinical Decision-Making Process
First, check the blood bank records or LIS (Laboratory Information System) to confirm if transfusions were administered 2.
If transfusions were documented, the result can be reported with an appropriate comment noting recent transfusion.
If no transfusions were documented, then consider other possibilities:
- Specimen mislabeling or patient misidentification
- Pre-analytical errors in sample collection
- Significant changes in plasma volume affecting hemoglobin concentration 3
Clinical Context
Current transfusion guidelines recommend restrictive transfusion strategies with hemoglobin thresholds of 7-8 g/dL for most stable hospitalized patients 1, 4. The initial hemoglobin of 7.8 g/dL falls within this range where transfusion might be considered based on clinical factors, making it plausible that this patient received blood products.
Laboratory professionals play a critical role in identifying potentially erroneous or clinically significant changes in laboratory values. Proper investigation of delta flags helps ensure accurate patient results and appropriate clinical decision-making.