Manual of basic techniques for a health laboratory - libdoc.who.int

262 Manual of basic techniques for a health laboratoryMethodFor determination of glucose concentrations in the CSF, all methods that are usedfor determination of blood glucose concentrations can be applied. When theorthotoluidine method (see section 10.1) is used, four times more CSF is neededthan in the test on blood.Important: As the glucose in the CSF is rapidly destroyed once the fluid is collected,it is important to carry out the estimation of glucose concentration as soon as possible.If there is likely to be a delay, the CSF should be preserved in fluoride oxalate(reagent no. 26).8.3.5 Determination of protein concentrationPrincipleThe total protein concentration in the CSF is measured by diluting the CSF insulfosalicylic acid and comparing the cloudiness produced against a set of proteinstandards.A raised globulin level in the CSF is shown by adding the CSF to a phenol solutionin the Pandy test (see below).Fig. 8.18 Materials and reagents fordetermining the proteinconcentration of CSFMaterials and reagents (Fig. 8.18)●●●●●●CSF: centrifuge the CSF at 2000g for 5 minutes and use thesupernatant fluidGraduated pipettesDropping pipettesTest-tubesTest-tube rackBlack cardboard● Sulfosalicylic acid, 3% solution (reagent no. 57)● Pandy reagent (reagent no. 41)● Protein standards (see section 7.2.5).Fig. 8.19 Comparing a test sample againstthe protein standardsMethod for determination of total protein1. Pipette 3ml of sulfosalicylic acid into a test-tube that matches thestandard tubes.2. Add 1ml of clear CSF supernatant fluid and mix. Leave the tubefor 5 minutes.3. Compare the cloudiness of the test sample against the proteinstandards (Fig. 8.19). Record the concentration of protein in theCSF in g/l.The normal concentration of protein in the CSF is 100–450mg/l. The proteinconcentration is increased in:— meningitis, subarachnoid haemorrhage or constriction of the spine;— African trypanosomiasis.Method for determination of globulin (Pandy test)1. Measure 1ml of Pandy reagent into a small test-tube.2. Place the tube in front of a piece of black cardboard.