How is fetomaternal hemorrhage calculated?
The amount of fetal maternal hemorrhage is calculated by multiplying the percent fetal cells by 50. This calculation assumes that maternal blood volume is 5000 mL or 50 dL. This product is then divided by 30, which is the volume of fetal whole blood neutralized by a single vial of RhIg (300 ug dose).
What is fetomaternal hemorrhage?
Fetomaternal hemorrhage refers to the entry of fetal blood into the maternal circulation before or during delivery. Antenatal fetomaternal hemorrhage is a pathological condition with a wide spectrum of clinical variation.
How is Kleihauer betke calculated?
- Calculate Maternal Blood Volume (ml) = (Pre-pregnant weight in kg) x 70 ml/kg x. (1.0 + (0.5 x weeks gestation/36)) –
- Calculate Fetal Whole Blood (ml) = (Fetal Cell Count/Maternal Cell Count) x. Maternal Blood Volume.
- Rh Immune Globulin (RhoGAM) Dose. Give 300 ug per 30 ml fetal whole blood or 15 ml pRBC.
How do we determine the FETO maternal hemorrhage FMH in KB test?
The Kleihauer Betke test is utilized to determine if there is fetal blood in maternal circulation, with a threshold of 5 mL. The rosette test is performed by incubating the Rh-negative maternal venous whole blood sample with anti-Rho(D) immune globulin.
What causes Fetomaternal hemorrhage?
Obstetric Issues, Labor, and Delivery Fetomaternal hemorrhage is caused by a disruption of the normal barrier at the placental-decidual interface.
What is a positive KB test?
With a positive KB test, the significant risk of pre-term labour mandates detailed monitoring. KB testing has important advantages to all maternal trauma victims, regardless of Rh status.
How common is Fetomaternal hemorrhage?
Fetomaternal hemorrhage (FMH) refers to the passage of fetal blood into the maternal circulation before or during delivery. The incidence of FMH is between 1/300 and 1/1500 pregnancies and has been reported to account for approximately 0.04 percent of stillbirths .
What is a normal Kleihauer-Betke test?
The normal range is 0 to 0.1% as reported by the lab. Calculations for Estimating the Number of Vials of Rhogam Needed: One 300 ml vial of RhIG will protect against 30 ml of D-positive fetal blood.
What is a positive Kleihauer-Betke test?
This is a qualitative test that reveals the presence of Rh positive fetal cells in maternal circulation. The Kleihauer-Betke test, or flow cytometry if available, is then needed to quantify the number of fetal cells in circulation, which leads to the appropriate dose of RhIg to administer.
What tests can be used to detect a Fetomaternal hemorrhage?
Answer: B—KB stain is used to determine the amount of fetomaternal hemorrhage (FMH). Rosette test is performed when one knows the fetus is Rh positive. Further, it is only a qualitative test (Answer A). The KB test can be used as a quantitative measure of fetal hemorrhage, regardless of the fetal Rh type.
What is KB blood test?
The Kleihauer–Betke (“KB”) test, Kleihauer–Betke (“KB”) stain, Kleihauer test or acid elution test, is a blood test used to measure the amount of fetal hemoglobin transferred from a fetus to a mother’s bloodstream.
How is KB test performed?
The KB stain uses the principle of differential resistance of fetal hemoglobin to acid. A blood film from mother’s blood is made and then exposed to acid to remove adult hemoglobin from the cells; fetal hemoglobin is resistant to acid and will remain.
How is the size of a fetomaternal haemorrhage ( FMH ) determined?
Despite earlier publications describing methods for assessing fetomaternal haemorrhage ( 7 National Blood Transfusion Services, Immunoglobulin Working Party, 1991; 8) it is recognized that there is little standardization of techniques ( 3 ), a fact which can lead to inaccuracies in determining the size of any fetomaternal haemorrhage (FMH).
How to calculate FMH in ml of fetal RBC?
One of the formulas used to calculate FMH in ml of fetal RBC’s is – [number of fetal cells/ number of adult cells x maternal RBC volume].8 Many places use the assumption of average term woman weight of 70Kg and maternal RBC volume of 75ml/kg, giving maternal RBC volume of 5250 mls (=70×75).
Which is the best test for fetomaternal FMH?
Assessment of FMH can be achieved with flow cytometry using commercially available antibodies to the Rh D antigen or to Haemoglobin F [HbF]. In situations where the mother is known to be Rh D negative and the fetus is known to be Rh D positive the use of anti-D provides sensitive and accurate assessment of FMH, and
How to calculate the volume of a hemorrhage?
A = Length. B = Width. C = Slice Width. # Slices with Hemorrhage Present. Hemorrhage Shape: If Round/Ellipsoid: 2; Otherwise: 3. (See references below for this update to the formula.) Of note, the volume of an ellipsoid is 4/3 × π × (ABC/2); when you estimate π to be ~3, the volume becomes ABC/2.