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

352 Manual of basic techniques for a health laboratoryAlkaline haematin D reagent (No. 8)Sodium hydroxide (NaOH)4 gTriton X-100 (or equivalent)25gDistilled water1000mlDissolve the sodium hydroxide in the distilled water in a clean conical flask. Stirusing a glass rod until the crystals have completely dissolved. Add the Triton X-100(or equivalent) and mix well. Filter the solution into a clean glass-stoppered reagentbottle, using Whatman No. 1 (or equivalent) filter-paper. Label the bottle“ALKALINE HAEMATIN D REAGENT” and write the date. Store at room temperature(20–25°C).Check the quality of the solution (see below).Alkaline haematin D (AHD) reagent will keep for several months at 20–25°C. If aprecipitate forms during storage, the reagent should be filtered before use.Note: Use filtered rainwater if distilled water is not available.Quality control of alkaline haematin D reagentAn alkaline haematin D standard solution (AHD standard) supplied by the centrallaboratory is used to test the quality of new batches of AHD reagent in peripherallevellaboratories.1. Fill a clean cuvette with distilled water. Place the cuvette in the cuvette chamberand adjust the haemoglobinometer or colorimeter to read zero at 540nmwavelength.2. Replace the distilled water with AHD reagent. The haemoglobinometer or colorimetershould read zero.3. Pipette 20ml of AHD standard into a test-tube containing 3ml of the freshlyprepared AHD reagent (1:150 dilution).4. Measure the haemoglobin concentration of the AHD standard (see section 9.3.2).5. Repeat the procedure using the previous batch of AHD reagent. Compare theresults.6. If the haemoglobin values differ by more than 5g/l, discard the freshly preparedAHD reagent and prepare a new batch, paying attention to accurate measurementof the constituents and the cleanliness of the glassware.The AHD standard stock solution will keep for 8 months at 4–8°C.Amies transport medium (No. 9)Charcoal, pharmaceutical grade 10.0gSodium chloride (NaCl) 3.0gDisodium hydrogen phosphate (Na 2HPO 4·2H 2O) 1.15gPotassium dihydrogen phosphate (KH 2PO 4) 0.20gSodium thioglycollate 0.10gCalcium chloride (CaCl 2), anhydrous 0.10gMagnesium chloride (MgCl 2) 0.10gAgar 4.00gDistilled water1000mlSuspend the mixture of salts in the distilled water. Add the agar and heat until theagar has completely dissolved. Add the charcoal. Dispense into small tubes or bottleswhile stirring to keep the charcoal evenly suspended.