Presentation on theme: "LABORATORY DIAGNOSIS OF ANAEMIA IN PREGNANT WOMEN"— Presentation transcript:
1LABORATORY DIAGNOSIS OF ANAEMIA IN PREGNANT WOMEN ANNETTE MOBITB.M.L.S (HONS.)LABORATORY SCIENTISTMEDICAL AND HEALTH SERVICESCDC
2INTRODUCTIONA knowledge of a patient’s symptoms and clinical history can often establish the cause of anaemia.Laboratory tests can help to identify the type of anaemia and monitor patient’s response during treatment.Techniques for measuring haemoglobin and assessing anaemia will also depend on available faculties and resources the Laboratory has in place.
3TECHNIQUES FOR DIAGNOSING ANAEMIA IN PREGNANCY Haemoglobin Measurement.Packed cell volume (haematocrit) measurementRed cell indicesBlood films ExaminationElectrophoresis to detect Haemoglobin sickle cells.Reticulocyte countPlatelet count
5Haemoglobin Measurement Anaemia occurs when the conc. of Hb falls below what is normal for a person’s age, gender and environment. Hb values are expressed in grams per litre (g/dl) or grams per decilitre (g/dl). Hb reference range will also depend on the method used, manufacturer’s produces and reference range.
6Hb Normal reference ranges Children at birth g/dl.Children (2-5) yrs g/dl.Children (6-12)yrs g/dl.Adult men g/dl.Adult women g/dl.Pregnancy women g/dl.
7Measurement Techniques Haemoglobin can be measured using two techniques.Photometric Techniques.Here the absorbance of Hb in blood sample is measured electronically using filter colorimeter or read out Hb meter.Visual comparative TechniqueThis is use when it is not possible to measure Hb accurately using a photometric techniquee.g -Who Haemoglobin colour scale.Sahli’s method (less reliable).
8Packed cell volume (PCV) or Haematocrit Measurement Packed cell vol (PCV) is the proportion of whole blood occupied by red cells expressed as a ratio PCV is also used to calculate red cell indices, which are also used to investigate anaemia.
9PCV VALUESPcv values vary according to age, gender and attitude, pcv is measured in litre.Children at birth l/lChildren (2-5) yrs l/lChildren (6-12)yrs l/lAdult men l/lAdult women l/l
10Measurement of Red cell indices. Red cell indices frequently used to investigate anaemia are:Mean cell haemoglobin conc.(MCHC).This gives the conc of Hb in gll in 1litre of packed red cells. That is calculated from Hb andPCVMCHC = Hb (g/l)Pcv (l/l).Normal Range – gll ( )gldl.
11MCHC, MCVMean red cell volume (MCV)-This gives the red cell size. It is determined from PCV and electronically obtained RBC count.MCV = PCV L/L = MCV fl.RBC x 1012/L fl= /LMean cell haemoglobin (MCH) –This gives the amount of Hb in an average red cell. It is determined from the Hb and RBC.MCH = Hb g/L = MCH pgRBC x 1012/L pg = /L
12EXAMINATION OF BLOOD FILMS This include thin blood films from finger pricking or bone marrow smear.Examination using thin blood films is important in the investigation and management of anaemia which produce changes in the appearance of red blood cells and differential white cell count.Analysing thin blood film includes the following:
13EXAMINATION OF BLOOD FILMS CONT. Differential white cell count and white cell morphology.Red cell morphology.Platelets.A differential white cell count provides information on the different white cells in the circulating blood, That isNeutrophilsLymphocytesMonocytesEosinophilsBasophils (rarely seen).
14Differential WBC reference range for adults. Cells PercentagesNeutrophils_______________40-75 %Lymphocytes______________21-40Monocytes________________ 2-10Eosinophils________________ 1-6Basophils_________________ 0.1-1
16Red Cell Appearance Size and Shapes. Normocytic – Normal red cell measuring about 8Nm in diameter.Microcytic – smaller than normal red cells having diameter less than 6.5Nm seen in iron deficiency anaemia.Macrocytic – Larger than normal red cells with diameter greater than 8Nm seen in Folate, vit B12 def anaemia.Sphecrocytosis – small densely staining spherical red cells with no central pallor seen in haemolytic anaemia’s.
17Red Cell Appearance Cont. Anisocytosis – unequal variation in the size of red cells. Seen in many anaemia’s.Pencil cells – Elongated narrow red cells seen in iron deficiency anaemia.Sickle cell – Elliptical cells with pointed ends or cresent shaped or boat shape cells. Seen in sickle cell anaemia.Schistocytes – Irregularly contracted red cell fragments often with projectionsseen in red cell damage due to burns, drugs, toxins, uraemia, and pre-eclampsia
18Red Cell Appearance Cont. Poikilocytosis – significant variation in cell shape seen in many anaemia’s.Reticulocytes (Nucleated Red cells)- Nucleus in red cell seen in sickle cell diseases.Megaloblast – Larger than normal red cells between (10-20) Nm with an immature nucleus with fine lacy chromatin pattern. seen in megaloblastic anaemia (def of folate or B12).
19Colour of Red blood cell (Haemoglobinization). Hypochromic – Pale staining red cells with increased area of central pallor.seen in ferrus def anaemia.Polychromasia – Blue –grey staining of immature red cells which are larger thannormal red cells. Seen in haemolytic anaemia.
20Platelets countThis can be requested to investigate mucosal bleeding with a decreased in platelet count usually below 20x109 /LNormal value x109/LAn increased in platelets count can be seen in iron def anaemia associated with active bleeding
21White Blood cell countcan be used to investigate infections Normal range in pregnancy 4-15x109 /Lleukopenia (decrease in WBC) can be seen in -Aplastic anaemia,Folate and vit B12 deficiency (megaloblastic anaemia).
22Other non frequent Anaemia investigations Stool Examination.For hook – worm ova. Microscopy for stool wet preparation and fecal occult blood test.Severe hook worm infection may lead to iron deficiency anaemia.Liver function TestYellowish plasma to detect Bilirubin conc.UrinalysisBlood in urine is an indication of haemolysis.
23Summary of red cell indices in common anaemia’s. MCHC MCV MCH.Ref value gldl fl pg.Anaemias.Normocytic N N NNormochromicMicrocyticHypochromice.g Fe def.Macrocytic Ne.g Folate Deficiency