Q.Visit a pathological laboratory to study various blood tests like Hb detection, CBC, blood groups.

A pathology laboratory measures haemoglobin (colorimetrically or with an automated analyser), counts the formed elements in a complete blood count (RBC, WBC and platelet counts, haematocrit, the differential WBC count), and types blood by agglutination with anti-A, anti-B and anti-D sera.

Suggested plan.

1. Before the visit - revise sections 8.9-8.12 (plasma, RBCs, WBCs, platelets) and prepare a table with columns: test, sample, method or instrument, normal value, what a high or low value means.
2. Haemoglobin (Hb) - note how a measured volume of blood is lysed and the colour of the haemoglobin derivative is compared against a standard (Sahli's acid-haematin method or a colorimeter/automated analyser). Normal: about 14-17 gm% in men and 13-15 gm% in women; a low value indicates anaemia.
3. Complete blood count (CBC) - watch the automated cell counter (or the haemocytometer and stained smear) give the total RBC count, total WBC count, platelet count, haematocrit and the differential count of the five WBC types. Note which values change in infection (leucocytosis), in dengue (thrombocytopenia) and in anaemia.
4. Blood groups - observe a drop of blood mixed with anti-A, anti-B and anti-D (Rh) sera; agglutination with a serum means the corresponding antigen is present on the RBCs. Record how the group is read off the pattern of clumping.
5. Report - the completed table, the precautions observed (sterile lancet, gloves, disposal of sharps), and one paragraph on why each test is ordered. The same blood-cell vocabulary appears in the NCERT/CBSE Class 11 chapter on body fluids and circulation, so the report serves CBSE students too.