Pediatric Transfusion Calculator - Weight-Based pRBC mL Dose

The pediatric transfusion calculator is a weight-based clinical tool that returns the volume of packed red blood cells to transfuse in millilitres for a child, using the Davies 2007 formula weight (kg) times the aimed increment in hemoglobin (g/dL) times 3 divided by the packed red cell product hematocrit. With a UK standard pRBC hematocrit of 0.60, the formula predicts that 10 mL per kg of packed red cells raises the child's hemoglobin by about 2 g/dL.

• • Pediatric intensive care transfusion planning: PICU teams use the calculated volume to set the blood bank order for post-operative or septic anemia, and to keep the mL per kg dose inside the Davies safety range.
• • Pediatric hematology chronic transfusion: Hematology teams use the same weight and increment to plan a chronic transfusion visit for thalassemia or sickle cell disease.
• • Caregiver and trainee education: Parents, residents, and students can use the calculator to anchor intuition for why a 10 kg infant needs 100 mL of pRBC for a 2 g/dL increment.

Pediatric transfusion volumes are weight-based because the total blood volume of a 1.5 kg premature neonate and a 60 kg adolescent are very different, and a flat adult rule of one unit of pRBC does not transfer.

When the team needs the total circulating blood volume in mL to set the transfusion threshold, Pediatric Blood Volume Calculator returns the age-banded Linderkamp mL per kg estimate that the calculated volume is compared against.

The calculator multiplies the child's weight in kilograms by the aimed increment in hemoglobin in g/dL, then multiplies by 3, and finally divides by the decimal packed red cell product hematocrit. The mL per kg dose is echoed back so the team can confirm the result against the standard 10 mL per kg per 2 g/dL rule.

• Weight (kg or lb): Most recent measured weight. Pounds are converted to kilograms at 1 kg = 2.2046 lb. Range 0.5 to 150 kg.
• Hemoglobin increment (g/dL): Aimed increase in hemoglobin. Default 2 g/dL. Routine pediatric increments sit between 1 and 4 g/dL. The current and target hemoglobin fields derive this value when both are entered.
• Packed red cell hematocrit (percent): Hematocrit of the transfused pRBC product. UK and US products typically sit at 55 to 70 percent. The formula divides by the decimal form.
• Current and target hemoglobin (optional): When both are entered, the calculator derives the increment. Leave both at 0 to use the direct increment field.

The same formula underpins chronic transfusion planning in pediatric hematology and the perioperative maximum allowable blood loss calculation.

According to Davies et al. 2007, the pediatric transfusion volume should be calculated as weight (kg) times the aimed increment in hemoglobin (g/dL) times 3 divided by the hematocrit of the packed red cell product, and a UK standard hematocrit of 0.60 predicts that 10 mL per kg of packed red cells raises the child's hemoglobin by about 2 g/dL.

When the team moves from the packed red cell volume to the actual weight-based drug dose that needs to be diluted or infused at the bedside, Pediatric Dose Calculator carries the same kilogram weight and applies the mg per kg rate.

Four concepts anchor the calculator: the weight x increment x 3 / hematocrit multiplication, the mL per kg dose echo, the whole blood equivalent, and the difference between transfusion in a stable versus actively bleeding child.

Most bedside teams quote the Davies formula as the 10-20-30 rule: 10 mL per kg raises hemoglobin by 2 g/dL, 20 mL per kg by 4 g/dL, 30 mL per kg pushes toward hypervolemia.

When the packed red cell volume is interpreted alongside the child's blood pressure to assess perfusion, Pediatric Blood Pressure Calculator organizes the systolic and diastolic reading against the AAP pediatric blood pressure reference for the same age band.

Work in the same order the bedside team would: pick the child's weight, decide on the aimed increment, and confirm the packed red cell product hematocrit from the blood bank.

1. 1 Enter the child's weight: Use the most recent measured weight. Switch the unit toggle to lb if the chart has pounds; the calculator converts at 1 kg = 2.2046 lb.
2. 2 Pick the aimed increment: Enter the aimed increase in hemoglobin. Default 2 g/dL. Optionally enter current and target hemoglobin to let the calculator derive the increment.
3. 3 Confirm the pRBC product hematocrit: Set the pRBC hematocrit to the value on the blood bank label. UK and US pRBC products typically sit at 55 to 70 percent.
4. 4 Read the packed red cell volume: The primary result is the pRBC volume in mL. The result panel also echoes the mL per kg dose and the whole blood equivalent.
5. 5 Order and document the transfusion: Quote the calculated volume in the chart note, set the order in the electronic medical record, and document the product hematocrit used.

A 12 kg toddler with iron-deficiency anemia moving from 6.5 to 9.5 g/dL: 12 x 3 x 3 / 0.60 = 180 mL, 15 mL per kg, inside the Davies safety range.

When the child also needs an oral antibiotic and the team wants to switch from an IV transfusion dose to a weight-based oral dose, Amoxicillin Pediatric Dosage Calculator walks through the same weight in kilograms and shows the corresponding liquid dose.

A pediatric transfusion calculator makes the Davies 2007 formula consistent across providers, traceable in the chart, and quick to revisit when the child's weight, current hemoglobin, or product changes.

• • Consistent Davies 2007 dose across providers: PICU, hematology, anesthesia, and blood bank teams use the same formula, which removes the inconsistency of bedside mental math and rounds to the same volume.
• • Transparent result with mL per kg echo: The result panel echoes the mL per kg dose, so a later reviewer can see which Davies rule was applied and whether the dose sits inside the safety range.
• • Optional current and target hemoglobin: When the chart has the latest hemoglobin, the team can enter the current and target values to let the calculator derive the increment, which removes the most common mental-math error of subtracting the wrong baseline.
• • Whole blood cross-check: The result panel shows the equivalent whole blood volume at a hematocrit of 0.40, so the team can switch products without re-doing the math.
• • Weight unit flexibility: The kg / lb toggle accepts weights in either unit, matching growth charts, anesthesia records, and triage notes from the emergency department.

The calculator is a teaching tool: a trainee who sees 100 mL for a 10 kg infant and 375 mL for a 25 kg child can remember the linear scaling of the Davies formula.

When the child needs fresh frozen plasma alongside the packed red cells for coagulopathy or warfarin reversal, Fresh Frozen Plasma Dose Calculator returns the matching 10 to 15 mL per kg plasma dose.

The packed red cell volume is shaped by the child's weight, the aimed increment, the packed red cell product hematocrit, and the local safety range for the mL per kg dose. The whole blood equivalent uses a fixed whole blood hematocrit of 0.40.

• • The Davies formula was derived in a PICU population of 379 transfusions. Real pediatric increments can vary by 10 to 15 percent, especially in critically ill children, in children on vasopressors, and in children with active bleeding.
• • The pRBC product hematocrit is a fixed input. Products in different additive solutions (CPD, CPDA-1, AS-1, AS-3) have different hematocrits, so the team should pull the actual hematocrit from the blood bank label.

The weight, increment, and product hematocrit together cover most of the variance. The whole blood equivalent is a quick check.

According to Lacroix et al. 2007 (TRIPICU), restrictive packed red cell transfusion with a hemoglobin trigger of about 7 g/dL in stable pediatric intensive care patients produced outcomes no worse than a liberal 9.5 g/dL trigger, supporting the bedside 10 mL per kg per 2 g/dL target increment in stable children.

According to Bharadwaj et al. 2014, perioperative pediatric transfusion should be planned in mL per kg of packed red cells from an age-banded blood volume estimate, with the product hematocrit, the starting hemoglobin, and the aimed hemoglobin increment all factored in to minimize hypervolemia and donor exposure.

When the child's recorded weight reflects fluid overload from the transfusion or severe obesity, Adjusted Weight Calculator returns the adjusted body weight that should be used in the next packed red cell calculation.