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HDN DUE TO RHESUS INCOMPATIBILITY


Rhesus HDN is usually caused by immune anti-D and less commonly by other Rhesus antibodies. It occurs when a Rh negative mother with circulating IgG anti-D antibody (formed from a previous Rhesus
incompatible pregnancy) becomes pregnant with a Rh positive infant and IgG anti-D passes into the fetal circulation, destroying fetal cells. The infant can
be born severely anaemic and jaundiced.

The severity of disease increases with each Rh positive pregnancy. Infants with Rhesus HDN are usually more severely affected than infants with ABO HDN.
Note: In most cases of Rhesus HDN, maternal IgG anti-D will have been detected by the laboratory during routine antenatal visits, and the strength of the antibody (titre), monitored.
When Rhesus testing is not performed routinely (due to low frequency of Rh negative persons in the population) and an infant is born severely anaemic
and jaundiced, the laboratory may be asked to investigate the possibility of Rhesus HDN.

See also:laboratory investigation of HDN

TUBE METHOD FOR BLOOD GROUPING


1. Take five small (e.g. 63 9.5 mm) tubes* and label them 1 to 5.
When reusing tubes for blood transfusion work, use glass tubes because it is difficult to completely clean plastic tubes of traces of protein or detergent.

2. Pipette into each tube as follows:
Tube 1 : 1 volume anti-A serum
1 volume 3–5% patient’s
red cells
Tube 2 : 1 volume anti-B serum
1 volume 3–5% patient’s
red cells
Tube 3:. 1 volume patient’s serum
1 volume 3–5% A cells
Tube 4: 1 volume patient’s serum
1 volume 3–5% B cells
Tube 5: 1 volume patient’s serum
(Auto- 1 volume patient’s 3–5%
control) red cells

3. Mix the contents of the tubes by gently tapping the base of each tube with the finger.

4. Leave the tubes at room temperature for 5 minutes. Centrifuge at lowest setting (e.g. 150 g) for 1 minute or at 500–1 000 g for 10–15 seconds.

5. Replace the tubes in the rack in the same
position as before centrifuging. Read the results by tapping gently the base of each tube, looking for agglutination or haemolysis. Record the results in the Blood Grouping Book and on the patient’s form. Interpret the results as follows:

Tube1 Tube2 Tube3 Tube4 Tube5 B/G
Anti-A Anti-B A cells B cells Ctrl.
+ – – + – A – + + – – B + + – – – AB – – + + – O

Haemolysis is recorded as a positive (+) reaction. When a reaction is weak, record this (WK).
Group O donor blood found to contain anti-A and anti-B haemolysins should be labelled. Use as whole blood for group O patients only or use as concentrated red cells

Alkaline Phosphatase test (ALP)

ALP is an hydrolytic enzyme that reacts optimally at alkaline pH and is formed in the liver and almost all tissues of the body. It modulates activities of proteins inside the cell.

What does ALP results indicate?

Rise in ALP may be associated with bone metastases, hepato biliary diseases and hyperparathyroidism.

Low levels of ALP is uncommon and occurs in about 0.2% of old people.

ALP is a sensitive indicator of liver functioning

What are reference ranges for ALP?

Men……………..(<270 U/L)

Women…………(<240 U/L)