instruments in pathology.pptx

These are the various different instruments used in pathology in mbbs

1. INSTRUMENTS IN PATHOLOGY

2. Urinometer It is used to measure the specific gravity of urine. Enough amount of urine is taken in the container. The urinometer is then allowed to float freely and then specific gravity of urine is measured by reading graduation on stem. Normal specific gravity 1.016 -1.022. Other methods of specific gravity- Falling drop method using chloroform and benzene Refractometer Multisticks Correction of specific gravity has to be done in temperature, glucose and protein in urine.

3. SAHLI’S HAEMOGLOBINOMETER

4. Uses: Estimation of Haemoglobin by Sahli’s Acid Haematin Method.

5. Hb count by Sahli's haemoglobinometer (acid haematin method): Principle:  Anticoagulated blood is added to the 0.1 N HCl and kept for 5-7 minutes to form acid haematin . The color of this acid haematin should be matched with the solution, present in the calibration tube. Distilled water is added to the acid haematin until the color matches and the final reading is directly noted from the graduation in the calibration tube. [Please note that 100 percent on the scale corresponds to 14.5gm % to 15gm Requirements:   Sahli's haemoglobinometer , Hydrochloric acid, distilled water. Procedure:  Place N/10 HCL in diluting tube up to the mark 20. Take blood in the haemoglobin pipette up to 20-cubic-mm-mark and blow it into diluting tube and rinse well. After 10 minutes add distilled water in drops and mix the tube until it has exactly the same color as the comparison standards. Note the reading, which indicates the percentage o Result:  The Hb estimation of the given sample is ..... g/100 ml of blood/.....g/dl of blood/.....G%. Precautions:  i . Pipetting of blood should be done cautiously ii. Mix the blood properly with HCl by using stirrer iii. Match the color cautiously.

6. ESBACH’S ALBUMINOMETER

7. Esbach's Albuminometer ; for testing the albumen in urine. Esbach's albumenometer used a simple chemical test to measure the amount of the protein albumen in urine. The instrument is made of glass and wood. It is contained in a wooden case. Urine was filled to the ‘U’ mark and a chemical reagent to the ‘R’ mark. The substance stood for 24 hours before the protein levels were assessed. Unusual levels of albumen in the urine can indicate kidney problems. It is named after its inventor, French physician, G H  Esbach (1843).

8. It is mixed by inverting it at least 12 times. It is kept in cool and dark place to prevent the precipitation of picrates . The protein precipates is settled down in the bottom. The amount of protein is read in gm/ litre .

9. Composition of ESBACH’s Reagent Citric acid-20 gm Picric acid -10gm Distilled water-1litre

10. NEUBAUER’S CHAMBER

11. The hemocytometer (or haemocytometer or counting chamber) is a specimen slide which is used to determine the concentration of cells in a liquid sample. It is frequently used to determine the concentration of blood cells (hence the name “ hemo -“) but also the concentration of sperm cells in a sample. The cover glass, which is placed on the sample, does not simply float on the liquid, but is held in place at a specified height (usually 0.1mm).

12. Additionally, a grid is etched into the glass of the hemocytometer . This grid, an arrangement of squares of different sizes, allows for an easy counting of cells. This way it is possible to determine the number of cells in a specified volume.

13. WBC PIPETTE and RBC PIPETTE

14. RBC pipette consists of a red bead inside the bulb, where as WBC pipette consists of a white bead inside the bulb. RBC pipette is cleaned by rinsing with water, then alcohol & then with acetone, where as WBC pipette is cleaned by rinsing with 2% v/v acetic acid because it lyses RBC's leaving only WBC visible

15. WBC Diluting fluid: Ideal diluting fluid should dilute the blood, destroy RBC but not WBCs and stain the nucleus of WBCs Diluting fluid used is Turk’s fluid. Composition: Gentian violet - 0.025gm Glacial acetic acid - 2cc Distilled water upto – l00 mL Gentian violet stains the nucleus of WBCs. Glacial acetic acid destroys the RBCs by hemolysis .

16. Other uses of WBC pipette: 1. Cell count in C.S.F. 2. Sperm count 3. Absolute Eosinophil count 4. R.B.C. count in severe anaemia

17. R.B.C diluting fluid: Hayem’s fluid is the commonly used diluting fluid.  Composition:  Sodium chloride 0.5 Gm Sodium sulphate 2.5 Gm Mercuric perchloride 0.25 Gm Distilled water 100 ml Sodium chloride and sodium sulphate together keeps the isotonicity of fluid. Sodium sulphate also prevents clumping of red cells. Mercuric perchloride fixes the cells and acts as a preservative

18. Other uses of R.B.C. pipette: 1. WBC count in leukemias 2. Platelet counting Uses of the bead in the bulb 1. For proper mixing 2. To know whether the pipette is dry 3. To identify the pipette

19. Westergreen’s Tube Westergreen’s Tube (pipette) is a long cylindrical thick glass tube of 300 mm length and 2.5 mm bore diameter. It is open at both ends and is graduated from 0 to 200 in mm scale from top to bottom. The markings are only over the lower 2/3rds of the tube. The anticoagulant used is sodium citrate of concentration 3.8%. Proportion of anticoagulant to blood is 1:4. Other methods Wintrobes’s method: Wintrobe’s heamatocrit tube is used as in the other method, for determining ESR.

20. Wintrobe’s tube This is 11 cm long tube with 3mm bore It is closed at one end .It is graduated in two scales.It is marked 0 at bottom and 10 at top for estimation of PCV and 0 at top and 10 at bottom for estimation of ESR. Anticoagulant EDTA used in ratio 1:4 . Used for estimation of ESR, PCV and preparation of buffered coat.

21. WINTROBE TUBE

22. ELISA TRAY

23. ELISA Microplate having 96 well. An ELISA test uses components of the immune system and chemicals to detect immune responses in the body (for example, to infectious microbes). The ELISA test involves an enzyme (a protein that catalyzes a biochemical reaction). It also involves an antibody or antigen (immunologic molecules). ELISA tests are widely utilized to detect substances that have antigenic properties, primarily proteins (as opposed to small molecules and ions such as glucose and potassium). The substances detected by ELISA tests include hormones, bacterial antigens and antibodies.

24. BLOOD SAMPLE COLLECTION VIALS

25. Lavender /purple cap –EDTA used for estimation of Blood counts , ESR, PCV . Red cap –plain or no anticoagulant used for immunology , serology Grey cap- sodium floride . Used in glucose estimation. Light blue- 3.8% tri-sodium citrate used for ESR and coagulant studies. Green cap –Heparin tube . U sed for osmotic fragility test and immunophenotyping Yellow-contain citrate for blood culture.

26. EDTA

27. The interior of the tube wall is coated with sodium heparin, lithium heparin, or ammonium heparin The anticoagulant heparin activates antithrombins , thus blocking the coagulation cascade and producing a whole blood / plasma sample instead of clotted blood plus serum Green tops

28. Lithium Heparin: Contains an inert gel for separating plasma, which acts as a barrier between cells and plasma after centrifugation. Light Green top

29. Red cell anticoagulants and preservation Citrate Calcium-chelating agent Prevents coagulation by interfering with calcium-dependent steps in the coagulation cascade Citrate-dextrose The dextrose provide nutrient for red cells Support the generation of ATP by glycolysis thus enhancing red cell viability and extending shelf life upto 12 days Acid-citrate-dextrose Contains citric acid, sodium citrate, and dextrose Shelf life of 21 days and now no longer use for red cells as other solution are available with extended shelf life of red cells Acid pH does not help in maintaining 2,3-DPG levels Used in apheresis procedure

30. Citrate-phosphate-dextrose (CPD ) Alkaline pH helps in maintaining 2,3-DPG Shelf life is extended to 28 days CPD is not now commonly used Citrate-phosphate-dextrose-adenine (CPDA-1) Addition of adenine is associated with improved synthesis of ATP, allowing longer shelf life ( 35 days)

31. BLOOD : ANTICOAGULANT RATIO Volume of anticoagulant –nutrient solution is normally 1/7 volume of collected blood 14 ml of CPD/CPDA is used in preserving 100 ml blood 49 ml for a 350 ml collection 63 ml for a 450 ml collection

32. L.P. Needle Size-22 gauge (most commonly used) It is 90mm long needle Contains-needle and stylet Uses- Collection of CSF Guided FNAC of internal organ like lung , liver,kidney etc.

33. BM Examination needle Bone marrow aspiration needle- Salah, Klima and Islam needle Bone marrow biopsy needle- Jamshidi needle(6-12 gauge) –contains needle, obturator and stylet Use- Bone Marrow examination

34. Salah needle -It has a guard with side screw. Klima needle –no Guard in this needle. Uses: Criteria of BM Unexplained cytopenia MDL Suspected myeloproliferative disorders Plasma cell dysplasia CLL Pyrexia of unknown origin Parasites

35. Thermometer Types Liquid filled- Mercury/ alcohol Liquid crystal Electronic/digital Basal thermometers

36. Cassetes Disposable plastic cassetes for biopsy processing and embedding. Moulded from high density acetyl polymer A total 128 slots each measures 1x5 mm. Available in 11 colors

37. Microtome knife Planar concave Wedge shape Chisel shape Use- cutting of the tissue sections

38. Graduated Pipette Has a scale divided into one and of 1/10 of a millilitre Used when taking volume of solutions where much accuracy is not required.

39. Volumetric pipette Also known as bulb pipette-Allows extremely accurate measurement of volume of solutions Has a large bulb with along narrow portion above with a single graduation mark Typical volumes-10, 25, 50 ml

40. HAEMOGLOBIN PIPETTE It is a cylindrical specific pipette having only one marking of 20 cumm and no bulb . Used for Estimation of Haemoglobin by Sahli’s method.

41. Pasteur pipette/Dropper Used to transfer small quantities of liquids

42. Disposable syringe Capacity- 5ml to 20ml Uses-for giving injection for administration of drugs. For fine needle aspiration cytology.

43. Cervical Brush Used for taking samples screening of cervical diseases