PACKED CELL VOLUME ( or)HAEMATOCRIT DEFINED AS THE VOLUME OF PACKED RED CELLS IN A GIVEN SAMPLE OF BLOOD EXPRESSED AS A PERCENTAGE OF THE TOTAL VOLUME OF THE BLOOD SAMPLE PACKING THE RED CELLS IS ACHIEVED BY CENTRIFUGING A COLUMN OF BLOOD IN A GLASS TUBE 3/OCTOBER /2017 G.VANI 8
PACKED CELL VOLUME (or)HAEMATOCRIT IN ORDER TO STANDARDIZE THE DEGREE OF PACKING DURING CENTRIFUGATION, IT IS NECESSARY TO HAVE (1) OPTIMUM SPEED OF THE CENTRIFUGE (11) OPTIMUM RADIUS OF THE CENTRIFUGE (111)OPTIMUM DURATION OF CENTRIFUGING 3/OCTOBER /2017 G.VANI 9
PACKED CELL VOLUME (or)HAEMATOCRIT DETERMINATION OF PCV SIMPLE VERY ACCURATE METHOD OF ESTIMATING THE RED BLOOD CELL MASS IN THE BLOOD OF TELLING WHETHER THE PATIENT IS NORMAL ANAEMIC OR INCREASED RBC MASS(POLYCYTHEMIA) 3/OCTOBER /2017 G.VANI 10
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PACKED CELL VOLUME (or)HAEMATOCRIT METHODS OF ESTIMATION OF PCV 1.MACRO METHOD USING WINTROBE’S METHOD 2.MICROMETHOD USING CAPILLARY TUBE 3.AUTOMATED ANALYZER 3/OCTOBER /2017 G.VANI 17
PACKED CELL VOLUME (or)HAEMATOCRIT ANTICOAGULANTS USED : EDTA SAMPLE , HEPARIN OR DOUBLE OXALATE (THE SPECIMEN NEED NOT BE A FASTING SAMPLE) PRINCIPLE: WHEN ANTICOAGULATED BLOOD IS CENTRIFUGED IN A HAEMATOCRIT TUBE AT HIGH SPEED,THE ERYTHROCYTES SEDIMENT AT THE BOTTOM.THE RED CELL COLUMN IS CALLED AS PACKED CELL VOLUME(OR) HEMATOCRIT (CELL VOLUME%) 3/OCTOBER /2017 G.VANI 18
REQUIREMENT SPECIMEN WINTROBE TUBE PASTEUR PIPETTE (OR ) A SYRINGE WITH NEEDLE CENTRIFUGE WINTROBE TUBE SPECIALLY THICK WALLED GLASS TUBE GLASS TUBE 11 cm LONG INTERNAL DIAMETER 3 mm FLAT INNER BASE CALIBRATED HOLDS 1ml OF BLOOD 3/OCTOBER /2017 G.VANI 19
PACKED CELL VOLUME (or)HAEMATOCRIT PROCEDURE MIX THE BLOOD SAMPLE CAREFULLY LABEL A WINTROBE TUBE FILL THE TUBE USING PASTEUR PIPETTE OR A SYRINGE UP TO THE 100 MARK (USE A NEEDLE OF WIDE BORE TO PREVENT MECHANICAL BREAK DOWN OF RED BLOOD CELLS) AVOID TRAPPING OF AIR BUBBLES PLACE THE TUBE IN A CENTRIFUGE CUP(USE ANOTHER EMPTY WINTROBE TUBE FILLED WITH ANOTHER SPECIMEN) CENTRIFUGE FOR 30 MINUTES AT 3000 RPM 3/OCTOBER /2017 G.VANI 20
OBSERVATION AFTER THE BLOOD IS CENTRIFUGED ,THREE DEFINITE LAYERS CAN BE EASILY SEEN UPPER MOST LAYERS – IS PLASMA,PALE YELLOW IN COLOUR A THIN LAYER OF WBC AND PALTELETS WHICH IS JUST ABOVE THE RBC,WHICH IS GREYISH IN COLOUR CALLED THE ‘BUFFY COAT ’( BUFFY LAYER - NORMALLY IT IS 0.5 TO 1mm.EACH 0.1ml = 1000 CELLS per cu mm (µl) approximately) LOWER MOST LAYER OF RED CELLS ARE CLOSELY PACKED TOGETHER 3/OCTOBER /2017 G.VANI 21
COLOR AND OPACITY OF PLASMA EXPECTED CLINICAL CONDITIONS YELLOW JAUNDICE MILKY LIPEMIA CLOUDY MULTIPLE MYELOMA REDDISH HEMOLYSIS 3/OCTOBER /2017 G.VANI 22
OTHER USE OF WINTROBE TUBE USED FOR ESR ESTIMATION THE WESTERGREN METHOD IS PREFERRED AS IT IS MORE ACCURATE 3/OCTOBER /2017 G.VANI 23
CAPILLARY TUBE AFTER CENTRIFUGED 3/OCTOBER /2017 G.VANI 28
MICROHEMATOCRIT READER 3/OCTOBER /2017 G.VANI 29
TAKEN READING AFTER THE CENTRIFUGE 3/OCTOBER /2017 G.VANI 30
MICROHAEMATOCRIT METHOD SPECIMENS EDTA OR OXALATED SPECIMEN(USE PLAIN CAPILLARY TUBES) CAPILLARY BLOOD(USE HEPARINIZED BLOOD) PRINCIPLE BLOOD IS CENTRIFUGED IN A SEALED CAPILLARY TUBE AND PCV IS DETERMINED BY, A SPECIAL HEMATOCRIT READER REQUIREMENTS HEMATOCRIT CENTRIFUGE HEMATOCRIT READER CAPILLARY HEMATOCRIT TUBES SOFT WAX OR MODELLING CLAY 3/OCTOBER /2017 G.VANI 31
PROCEDURE DRAW THE SPECIMEN INTO AN APPROPRITATE CAPILLARY TUBE FILL IN THE TUBE TO ABOUT 2/3 LENGTH SEAL BOTH THE ENDS OF THE TUBE WITH SOFT WAX OR MODELLING CLAY IT IS PLUGGED TO A DEPTH OF ABOUT 1 CENTIMETER PLACE THE TUBE WITH ANOTHER SIMILAR TUBE IN THE RADIAL GROOVES OF THE CENTRIFUGE HEAD EXACTLY OPPOSITE TO EACH OTHER CLOSE THE CENTRIFUGE COVER AND CENTRIFUGE THE TUBES AT HIGH SPEED 15,000 RPM FOR 5 MINUTES 3/OCTOBER /2017 G.VANI 32
REMOVE THE CAPILLARY TUBE OBSERVATION IT WILL SHOW THREE LAYERS 1.CLEAR PLASMA AT THE TOP 2.WHITISH- BUFFYCOAT AT THE MIDDLE 3.COLUMN OF RED AT THE BOTTOM READ PCV AS FOLLOWS HOLD THE TUBE AGAINST THE HEMATOCRIT SCALE SO THAT THE BOTTOM OF THE COLUMN OF RED CELLS IS ALIGNED WITH HORIZONTAL ZERO LINE THE HEIGHT OF CLAY MOVE THE TUBE ACROSS THE SCALE UNTIL THE LINE MARKED 1.0 PASSES THROUGH THE TOP OF THE PLASMA COLUMN 3/OCTOBER /2017 G.VANI 33
THE LINE THAT PASSES THROUGH THE TOP OR THE COLUMN OF RED CELLS GIVES THE VALUE OF PCV SOURCE OF ERROR HEMOYSZED SPECIME WILL YIELD FALSE LOW VALUES INADEQUATE MIXING OF BLOOD INCOMPETENESS OF PACKING MAY LEAD TO ERRONEOUS RESULTS ERROR UNDER OPTIMUM CONDITIONS IS ONLY ± 1% DISADVATAGES IT REQUIRES SPECIAL CENTRIFUGE DISPOSABLE CAPILLARY TUBES 3/OCTOBER /2017 G.VANI 34
ADVANTAGES AMOUNT OF BLOOD REQUIRED IS VERY SMALL EASILY BE OBTAINED FROM A FINGER PRICK EDTA blood TIME REQUIRED FOR CENTIFUGATION IS MUCH LESS 3/OCTOBER /2017 G.VANI 35
CLINICAL CONDITIONS FALL IN HEMATOCRIT ANEMIA HYDREMIA HEMORRHAGE CIRRHOSIS RENAL DISEASES NORMAL PREGNANCY 3/OCTOBER /2017 G.VANI 36
PREVIOUS YEAR QUESTION PAPER PCV ( 2MARKS) APRIL 2017 PACKED CELL VOLUME (AUGUST 2010/SEPTEMBER 2014 ) 5 MARKS WINTROBE,S TUBE (FEB/MARCH 2011) 3 MARKS BUFFY COAT (AUGUST 2010) 3 MARKS WHAT IS PCV? NAME THE INSTRUMENT ,ANTICOAGULANT AND NORMAL VALUES? (SEP/OCT 2008) PCV TUBE(WINTROB’S TUBE) 3 MARKS (AUGUST 2013) 3/OCTOBER /2017 G.VANI 38
PACKED CELL VOLUME NORMAL RANGE MEN : 42-52 % WOMEN :36-48% LATE PREGNANCY : 23-37% 3/OCTOBER /2017 G.VANI 39