(12) Patent Application Publication (10) Pub. No.: US 2009/0142797 A1 Zhang Et Al

Home , Bamifylline, Cafedrine, Propentofylline

US 20090142797A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2009/0142797 A1 Zhang et al. (43) Pub. Date: Jun. 4, 2009

(54) BLOOD DILUENT AND METHOD OF USE (30) Foreign Application Priority Data THEREOF Dec. 4, 2007 (CN) ...... 200710199.435.3 (75) Inventors: Lina Zhang, Shenzhen (CN); Dan Liu, Shenzhen (CN); Wenjuan Xu, Publication Classification Shenzhen (CN); Mulong Liu, (51) Int. Cl. Shenzhen (CN) C07D 487/04 (2006.01) Correspondence Address: CI2O I/00 (2006.01) MINDRAY CAO STOEL RIVES LLP (52) U.S. Cl...... 435/40.5:544/264; 544/265; 54.4/267; 201 S. MAIN STREET, SUITE 1100 544/274:544/273 SALT LAKE CITY, UT 84111 (US) (57) ABSTRACT (73) Assignee: SHENZHEN MINDRAY BO-MEDICAL ELECTRONICS Blood diluent for use in the analysis of blood components CO.,LTD., Shenzhen (CN) may include at least one purine compound or salt thereof. The blood diluent may also include at least one of alkali metal salt (21) Appl. No.: 11/966,713 and/or at least one organic buffers and/or inorganic buffer. The blood diluent may be utilized to stabilize blood cells (22) Filed: Dec. 28, 2007 during storage and facilitate the analysis thereof. Patent Application Publication Jun. 4, 2009 Sheet 1 of 11 US 2009/0142797 A1

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FIG. 1 Patent Application Publication Jun. 4, 2009 Sheet 2 of 11 US 2009/0142797 A1

Analysis report of Analysis report of hemology analyzer hemology analyzer No.: 10 No.: 102 Date: 2007-11-1919:29 Date: 2007-11-92:29 WBC 110 x 1 Of H WBC 11.2 x OfL H Lymphi 18 x 1 Of Lymph: 1.9 x 10/L Midi 13 x Of H Mid: 13 x 1 Of H Grani 7.9 x OfL H Grani 8.0 x 1 OIL - Lymph%. 16.3 % L. Lymph%. 17.1 % l Mid 1.6 % H Mich 11.2 96. H Gran% 72.1 % H Gran% 717 9 HGB 110 g/L HGB 108 g/L. L RBC 3.69 x 1 OIL RBC 3.52 x 10'? HCT 36.2 9 HCT 34.8 9 MCV 98.3 ft. H MCV 98.9 ft. MCH 29.8 pg MCH 30.6 pg MCHC 303 gll MCHC 310 g/L l ROW-CW 3.0 % RDWCW 12.9 % ROW-SD 52.8 f ROW-SD 52.0 ft. PLT 385 x Of H PLT . 429 x 1 OIL H MPV 110 f MPV 1.O. f. POW 6.3 POW 16.5 PCT O,423 % H PCT O.471 % H

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Analysis report of Analysis report of hemology analyzer hemology analyzer No.: 500 No.: 502 Date: 2007. -19 g:58 Date: 2007.9 22:02 WBC 12.4 x Of - WBC 12.0 x . Of Lymph 6 x 11 ymph? 1.4 x Of Midi O.9 x Of Midi 0.9 x 10/L Gari 9.9 x Of H Grani 9.7 x OIL Lymph%. 12.8 % L. Lymph%. 11.9 % i. Mid: 7.2 9, Mid 7.3 : Gran% 8O.O 9, - Gran% 80.8 % GB 107 g/L HGB 102 g/L RBC 3.53 x Of RBC 3.56 x Of C 34S HCT 34.8 NCW SS.C. f. H MCV 97.9 ft. MC 30.3 pg MC 28.6 pg. MCC 30 g/L. MCC 293 g/l. ROW.CV 3.5 % ROW-CW 33 ROWS) 52.8 ft ROW-SD 528 f. PT 3 O x Of - PT 328 x 1 Of - WW 1.5 ft. - MPV 116 f H POW 8.2 OW 8,3 PC 0.356 - PCT O,380

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Analysis report of Analysis report of hemology analyzer hemology analyzer No.: 225 No.: 2252 Date: 2007-1 - 9 2002 Date: 2007. - 19 22:3 WBC 2.2 x 1 Of - WBC 12, x 101. H Lymphii 2.2 x 10/L Lymphii 2.0 x 10'IL Vicii O x 1 Of - Midi O x Of H Garif 9.0 x 1 OIL H Grani 9.1 x Of Lymph%. 17.6 % L. Lymph% 169 % t Mid% 8.5 % Vick, 8.6 % Gran 73,9 % H Gran% 74.5 % GB 110 g/l. KGB 109 g/L RBC 3.64 x Of RBC 3.53 x Of HCT 35.5 % HCT 34,9 % . CW 97.7 f. MCV 99. f. WC 30.2 pg. WC 30.8 pg MCC 309 g/l. MCC 312 g/L. t RW-CV AO ROW-CW 4.2 ROWSO 63.5 ft H RDW-SO 56.9 ft. PL 288 x if PLT 29 x 1Ci MW 9 ft MPV 2.2 f POW 8.2 POW 16.3 PC O.342 - PCT O.355

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Analysis report of Analysis report of hemology analyzer hemology analyzer No.: 501 No.: SO3 Date: 2007- - 9 1911 Date: 2007.11.9 2:15 WBC 5 x Of - WBC 15 x OIL ymphi 1 4 x Of Lymphii 1.5 x 10/L Midi 1.4 x 10/L - Midi 4 x 1 Of Grani 8.7 x Of - Grani 8.8 x 1 Of Lymph%. 12.1 % Lymph%. 13.3 % . Mid 2.3 % - Mid 2.0 98 - Gran 75.6 % - Gian% 74,7 % HGB 113 g/l. HGB 113 g/l. RBC 3.49 x 1 Off RBC 3.47 x Of l HCT 35.3 9 CT 34, 6 l MCW 1 O2 f H MCW CO. f. C 32.3 pg - WCH 32.5 pg NCHC 320 g/l. MCC 325 g/l. ROW.CW 143 6 ROW-CW 4.4 % ROW-SD 56.9 ft - ROW.S.D 645 fl. PL 234 x 1 OIL PT 218 x 1 Of MPV 17 f. H MPV 4 f. PDW 8.0 POW 15.9 PCT O,273 % PCT O.248

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FIG.5 Patent Application Publication Jun. 4, 2009 Sheet 6 of 11 US 2009/0142797 A1

Analysis report of Analysis report of hemology analyzer hemology analyzer No.: 901 No.: 902 Date: 2007. - 9 1948 Date: 2007.1 - 9 2 52 WBC 11.8 x Of - WBC 12.. O x Of - Lymphii 1.5 x 101 Lymphit 1.5 x 10/ Micit 2 x Of - Midi 13 x Of H Gari 9 x Of Grani 9.2 x Of H Lymph%. 12.9 % Lymph%. 12.8 % l Mic O.O. 9 Mid% .3 Gran 77. 9 Gran% 76.9 % H GE 100 g/ HGB 99 g/L . RBC 36 x 0, RBC 3.67 x 11 C 35.6 % HCT 36.2 t WCW 98.7 f. MCW 98.8 ft VC- 27.7 pg MC 26.9 pg l WCHC 280 g/L. MCHC 273 g/L l ROW-CV O.7 9 RDW-CV 10.7 % l RDW-S 43.0 ft. ROW-SD 422 f PLT 218 x Of 2O3 x Of MW 14 f. H MPV 2 f OW 5.7 POW 5.8 pc 0.248 %. PCT 0.227

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BLOOD DILUENT AND METHOD OF USE examinations involve such parameters as hemoglobin (HGB) THEREOF concentration, red blood cell count (RBC), white blood cell count (WBC), platelet (PLT) count, hematocrit (HCT) level, RELATED APPLICATIONS mean cell volume (MCV), mean cell (erythrocyte) hemoglo 0001. This application claims priority to Chinese Patent bin (MCH), mean cell (erythrocyte) hemoglobin concentra Application No. 200710199435.3, filed Dec. 4, 2007, which tion (MCHC). is incorporated herein by reference in its entirety. 0013 Presently, many instruments produce cell data results along with diagrams of cell Volume distribution rep TECHNICAL FIELD resenting the distribution of cell populations in a sample. Such diagrams are often referred to as cell distribution histo 0002 The present disclosure relates to a blood diluent and grams. method ofuse thereof, and more particularly to a blood dilu (0014) Referring to FIG. 1, white blood cells treated with a ent for use in blood cell analyzers and method of use thereof. lysing agent (hemolytic agent) may be differentiated into the following cell Subpopulations: 1) Small-cell Subpopulation, SUMMARY which is primarily lymphocytes; 2) mononuclear-cell Sub 0003) A blood diluent for use in the analysis of blood population, or middle cell subpopulation (MID), which components is disclosed. In one embodiment, the blood dilu includes monocytes, eosinophils, basophils, juvenile cells, ent comprises one or more purine compounds or salts thereof and leukemia cells (if present); and 3) a large-cell Subpopu and/or at least one or more alkali metal salts and/or at least lation, which may primarily include neutrophils (GRAN). one or more organic buffers and/or inorganic buffers. The percentage of each subpopulation is calculated by the instrument according to the ratio of each Subpopulation rela BRIEF DESCRIPTION OF THE DRAWINGS tive to the total number of cells. The absolute number of each Subpopulation is obtained by multiplying the respective per 0004 FIG. 1 is a histogram illustrating distribution of centage by the total number of white blood cells in the white blood cell subpopulations obtained by a blood analyzer. sample. Therefore, the shape of the white blood cell histo 0005 FIGS. 2-4 are each a diagram of blood sample analy gram can be an important reference for clinical diagnosis. sis using one embodiment of the blood diluent of the present 0015. As routine blood examinations in foreign medical disclosure containing 0.05g/L, 0.5 g/L and 25 g/L of caffeine institutions mostly employ anticoagulant venous blood as the respectively. sample, foreign manufacturers of blood cell analyzers and 0006 FIGS. 5-6 are each a diagram of blood sample analy reagents often focus on the accuracy of counting and differ sis using one embodiment of the blood diluent of the present entiation in the whole-blood mode, with special consider disclosure containing caffeine, at pH 5.0 and 9.5 respectively. ation of such characteristics as osmotic pressure and conduc 0007 FIG. 7 illustrates a comparison of a blood sample tivity of the reagents. However, in the domestic practice, analysis using one embodiment of the blood diluent of the capillary blood is often collected as the sample when routine present disclosure containing aminophylline (right) with a blood examinations are conducted. Many domestic medical blood sample analysis without using a blood diluent of the institutions store the capillary blood for a long time after present disclosure (left). collection. However, improper storage of blood without a 0008 FIG. 8 illustrates comparison of a blood sample proper blood diluent, may result in unstable and inaccurate analysis using one embodiment of the blood diluent of the white blood cell histograms which may lead to the collection present disclosure containing theophylline (right) with a of erroneous data and to difficulties in clinical diagnosis. blood sample analysis without using a blood diluent of the 0016. The present disclosure provides a blood diluent, present disclosure (left). which allows prolonged storage of capillary blood and accu 0009 FIG. 9 illustrates comparison of a blood sample rate and stable counting and determination of such indexes for analysis using another embodiment of the blood diluent of the blood analysis as white blood cells, red blood cells, platelets present disclosure containing uric acid (right) with a blood and hemoglobin both in the whole blood mode and in the sample analysis without using a blood diluent of the present pre-dilution mode, and meanwhile ensures that the character disclosure (left). istics of white blood cell subpopulations would not be 0010 FIG. 10 illustrates comparison of a blood sample changed. analysis using one embodiment of the blood diluent of the 0017. In one embodiment, the present disclosure provides present disclosure containing caffeine (right) with a blood a blood diluent for use in the analysis of blood components, sample analysis without using a blood diluent of the present said blood diluent comprising one or more purine compounds disclosure (left). or salts thereof. Said blood diluent optionally further com 0011 FIG. 11 illustrates comparison of a blood sample prises a) one or more alkali metal salts; and/or b) one or more analysis usingyetanother embodiment of the blood diluent of organic buffers and/or inorganic buffers. the present disclosure containing hypoxanthine (right) with a 0018. In another embodiment, the present disclosure pro blood sample analysis without using a blood diluent of the vides a method for analyzing blood components, said method present disclosure (left). comprising the step of mixing a blood sample with one embodiment of a blood diluent of the present disclosure and DETAILED DESCRIPTION an optional lysing agent Such as a hemolytic agent. 0012. In the blood and hemopoietic organs of normal 0019. It is has been clinically shown that the present dis human beings, the number of each kind of blood cell may be closure can provide an accurate determination of various in a certain normal range, and each different kind of blood cell routine blood parameters and maintain the stability of white and each different stage of cell development have certain blood cell differentiation for more than 2 hours after the characteristics in morphology and structure. Routine blood collection of capillary blood. Moreover, the blood samples US 2009/0142797 A1 Jun. 4, 2009

stabilized with the blood diluent of the present disclosure are Suitable for analysis of blood components in various kinds of -continued blood cell analyzers under various detection conditions. 0020. One embodiment of the blood diluent of the present disclosure is used for diluting blood samples to provide a Suitable environment of conductivity and osmotic pressure for methods of cell detection that rely on electrical impedance ur. to stabilize various blood cells and for distinguishing their morphology. For example, one embodiment of the blood dilu ent of the present disclosure may be utilized to stabilize white theobromine blood cells to facilitate their separation into various subpopu lations based on electrical impedance, thereby achieving the 0024. According to the present disclosure, the stabiliza counting of white blood cell Subpopulations. tion of blood components such as white blood cells, red blood cells, platelets and hemoglobin etc., especially white blood 0021 “Purine compounds' as used herein refers to com cells, may be accomplished through the use of one or more pounds having the structure of pyrimidoimidazole fused ring purine compounds. system as shown below and derivatives thereof. 0025 Purine compounds or salts thereof for use in various embodiments of the blood diluent of the present disclosure, may include hypoxanthine or Xanthine compounds or salts thereof. Other embodiments of a blood diluent according to the present disclosure may include, but are not limited to, the following substances and derivatives and salts thereof: 0026 1. caffeine and derivatives thereof; 0027 2. theophylline and derivatives thereof, for example theophylline, aminophylline, choline theophyllinate, dipro 0022. The amino and hydroxy derivatives of purine are phylline, doxofylline, cafedrine, bamifylline, theobromine, widely present in animals and plants. Important drugs such as pentoxifylline, propentofylline, denbufyline etc.; 0028. 3. hypoxanthine orxanthine and derivatives thereof, theobromine, caffeine and theophylline may include purine for example hypoxanthine, Xanthine, 1-methylxanthine, compounds. The components of nucleic acids and metabolic 3-methylxanthine, 7-methylxanthine, 1,7-dimethylxanthine products thereof Such as Xanthine, hypoxanthine and uric etc.; and/or acid, also include all purine compounds. 0029 4. uric acid and derivatives thereof, for example 0023. More particularly, the structures of hypoxanthine, 1-methyluric acid, 1,3-dimethyluric acid, 7-methyluric acid Xanthine, caffeine, theophylline (theosine), uric acid, dipro etc. phylline (dyphylline) and theobromine are as follows: 0030 Those skilled in the art will recognize that the derivatives and salts of the one or more purine compounds may include, but are not limited to, salts formed with an acid, OH O salts formed with a base, esters, N-oxides, tautomers, Sol Vates, complexes, other Substances formed with other radicals N21 X HN e NX through covalent or noncovalent bonding and precursors or metabolic products thereof. lsN NM O1. N 2 NA 0031. In one embodiment, one or more purine compounds may be present in the blood diluentinanamount ranging from hypoxanthine Xanthine approximately 0.05 g/L to approximately 25 g/L. In another O O embodiment, one or more purine compounds may be present N / N in the blood diluent in an amount ranging from approximately 0.3 g/L to approximately 10 g/L. N X N X 0032. In one embodiment, one or more alkali metal salts may be used for providing a suitable conductivity and es N es N osmotic pressure for a blood diluent of the present disclosure. Caffeine theophylline In another embodiment, one or more alkali metal salts may be (theosine) selected from alkali metal sulfates, alkali metal halides and OH other alkali metal salts, including sodium Sulfate and sodium chloride. In one embodiment of a method of blood cell analy O O OH sis, a blood diluent may include conductivity in the range of H approximately 16 mS/cm (milliSiemens per centimetre) to HN N N N approximately 22 mS/cm. The conductivity may be identi fied, for example, by an instrument sold as METTLER326. In one embodiment of a method of blood cell analysis, a blood O1. N N O O1. N N d H H diluent may include osmotic pressure in the range of approxi uric acid mately 250 mOsm/Kg (milliosmoles per kilogram) to diprophylline approximately 350 mCSm/Kg. The osmotic pressure may be (dyphylline) identified, for example, by an instrument sold as OSMOM ETER SLAMED 800 c1. US 2009/0142797 A1 Jun. 4, 2009

0033. One embodiment of the blood diluent of the present Example 3 disclosure may contain buffers for adjusting the pH value of 0040. In this example, a blood diluent is made by mixing the blood diluent. The buffers may be those buffers com the following into a final volume of 1 L: monly used in the art including common buffering systems Such as formic acid, phthalic acid, acetic acid, phosphoric acid, TRIS, boric acid, carbonic acid and salts thereof. In one caffeine embodiment, the pH range of the blood diluent of the present sodium sulfate disclosure can be adjusted in the range of approximately pH sodium chloride 3i 5.0-9.5. phosphate buffer solution O.O add water to make 0034. The present disclosure also provides methods for pH 7.0 analyzing a blood sample or blood components, said method comprising mixing the blood sample with a blood diluent, according to the various embodiments of the present disclo Example 4 sure. Embodiments of the methods for analyzing a blood 0041. In this example, a blood diluent is made by mixing sample or blood components may include mixing the blood the following into a final volume of 1 L: sample with one or more lysing agents or hemolytic agents and determining the parameters of various components in the blood such as white blood cells, red blood cells, platelets, caffeine 0.5 g. hemoglobin. sodium sulfate 10 g sodium chloride 3.5 g. 0035. It is preferable to use a lysing agent, such as a phosphate buffer solution O.OS M hemolytic agent, to separate the red blood cells from the white add water to make a total volume of 1 L blood cells during the blood sample analysis. pH 5.0

EXAMPLES Example 5 0042. In this example, a blood diluent is made by mixing 0036. The various embodiments of a blood diluent accord the following into a final volume of 1 L: ing to the present disclosure are further described by way of the following examples. However, it is understood that the present disclosure is not limited thereto or thereby. caffeine O. 0037. In the following examples of preparation of the sodium sulfate 1 embodiments of a blood diluent of the present disclosure, the sodium chloride 3 blood diluent may be obtained by mixing the components as phosphate buffer solution O.O listed. add water to make pH 9.5 Example 1 Example 6 0038. In this example, a blood diluent is made by mixing 0043. In this example, a blood diluent is made by mixing the following into a final volume of 1 L: the following into a final volume of 1 L:

caffeine 0.05 g aminophylline O. Sodium Sulfate 10 g sodium sulfate 1 Sodium chloride 3.5 g. sodium chloride 3 phosphate buffer solution O.OS M phosphate buffer solution O.O add water to make 1 L add water to make pH 7.0 pH 7.0

Example 2 Comparative Example 1 0044. In this example, a blood diluent is made by mixing 0039. In this example, a blood diluent is made by mixing the following into a final volume of 1 L: the following into a final volume of 1 L:

N-(2-acetamido)-2-iminodiacetic acid (ADA) caffeine O. dimethylurea Sodium Sulfate 1 (2-pyridinethiol-1-oxide) sodium Sodium chloride 3 sodium sulfate phosphate buffer solution O.O sodium chloride add water to make phosphate buffer solution O.O pH 7.0 add water to make pH 7.0 US 2009/0142797 A1 Jun. 4, 2009

Example 7 0045. In this example, a blood diluent is made by mixing -continued the following into a final volume of 1 L: add water to make 1 L pH 7.0

theophylline O. Sodium Sulfate 1 Comparative Example 5 Sodium chloride 3 phosphate buffer solution O.O 0.052 The composition of the blood diluent is the same as add water to make that of Comparative Example 1. pH 7.0 Example 11 Comparative Example 2 0053. Each of the blood diluents obtained above is used in blood analysis. Mindray BC-3000 Plus blood cell analyzer 0046. The composition of the blood diluent is the same as (and BC-1800, BC-2800, BC-2300 blood cell subpopulations that of Comparative Example 1. analyzers) are employed herein. Those skilled in the art will recognize that blood cell analyzers from other manufacturers Example 8 or of other brands may also be adapted for use with the present 0047. In this example, a blood diluent is made by mixing disclosure. the following into a final volume of 1 L: 0054 During blood sample analysis, the numerous cells in the blood may overlap or clump together with each other potentially frustrating an accurate counting and Volume mea uric acid surement. As such, there exists a need to dilute the blood Sodium Sulfate sample with a blood diluent so that the diluted blood cells may Sodium chloride pass individually through a detection orifice of a blood cell phosphate buffer solution O s analyzer. Moreover, a blood diluent may provide an ionic add water to make environment which may be advantageous for blood cell pH 7.0 counting and the determination of cell number and Volume. 0055 One embodiment of the present disclosure may include a method wherein whole blood and the blood diluent Comparative Example 3 can be mixed to form a diluted sample having a first concen 0048. The composition of the blood diluent is the same as tration. Said diluted sample of the first concentration is that of Comparative Example 1. divided into two portions. One portion is mixed with a certain amount of the blood diluent to form a diluted sample having Example 9 a second concentration that is used for the counting of red blood cells and platelets. The other portion is mixed with a 0049. In this example, a blood diluent is made by mixing certain amount of a lysing agent to form a diluted sample of a the following into a final volume of 1 L: third concentration that is used for the counting of white blood cells. 0056. Another embodiment may include a pre-dilution caffeine O. method wherein there is an additional step called “dilution Sodium Sulfate 1 outside of the instrument, namely, the capillary blood Sodium chloride 3 sample is mixed with a certain amount of the blood diluent phosphate buffer solution O.O add water to make outside the blood cell analyzer to form a diluted sample pH 7.0 similar to the previously mentioned diluted sample of the first concentration. Following the pre-dilution method, sample analysis may proceed as disclosed for the whole blood Comparative Example 4 method. 0057. In one embodiment, the blood diluent of the present 0050. The composition of the blood diluent is the same as disclosure is adapted for all the dilution steps described that of Comparative Example 1. herein, and is especially adapted for the dilution steps in the pre-dilution method, wherein a lysing agent may include the Example 10 following formulation: 0.058 Lysing agent: 0051. In this example, a blood diluent is made by mixing the following into a final volume of 1 L:

triazole 10 g dodecyltrimethylammonium chloride (50% solution) 35 ml hypoxanthine 0.5 g. tetradecyltrimethylammonium bromide 3.5 g. Sodium Sulfate 10 g add water to make 1 L Sodium chloride 3.5 g. pH 6.19 phosphate buffer solution O.OS M US 2009/0142797 A1 Jun. 4, 2009

0059 FIGS. 2-11 show the related histograms of white What is claimed is: blood cells, red blood cells and platelets determined after the 1. A blood diluent for use in the analysis of blood compo capillary blood samples are mixed with the blood diluents of nents, said blood diluent comprising: the present disclosure. The samples as used are all collected at least one purine compound or salt thereof. from fresh clinical capillary blood samples. The left panels 2. The blood diluent according to claim 1, said blood dilu and the right panels in FIGS. 2-6 are the test results from the ent further comprising: same blood sample, with the left panels obtained on fresh at least one alkali metal salt; at least one organic buffer, sample (about 5 minutes after sampling) and the right panels and/or at least one inorganic buffer. 3. The blood diluent according to claim 1, wherein said at obtained on the same sample stored for at least 2 hours after least one purine compound or salt thereof includes at least one sampling. Each of FIGS. 7-11 shows a comparison of two sets hypoxanthine compound or salt thereof or at least one Xan of histograms of the same blood sample obtained using two thine compound or salt thereof. different blood diluents according to the present disclosure 4. The blood diluent according to claim 3, wherein said at (see the description of the titles of each figure). In each of the least one hypoxanthine compound or salt thereof or at least histograms, the left panels are obtained on fresh sample one Xanthine compound or salt thereof include Substances (about 5 minutes after sampling, not more than 10 minutes) selected from the group consisting of caffeine, theophylline, and the right panels are obtained on the same sample stored aminophylline, choline theophyllinate, diprophylline, dox for at least 2 hours after sampling. ofylline, cafedrine, bamifylline, theobromine, pentoxifylline, 0060 FIGS. 2-4, respectively, correspond to examples 1-3 propentofylline, denbu?yline, hypoxanthine, Xanthine, 1-me wherein the diluent contains caffeine in a concentration of thylxanthine, 3-methylxanthine, 7-methylxanthine, 1,7-dim 0.05 g/L, 0.5 g/L and 25 g/L, respectively. It can be seen from ethylxanthine, uric acid, 1-methyluric acid, 1,3-dimethyluric FIGS. 2-4 that the curves of the blood components (white acid, 7-methyluric acid and combinations, derivatives and blood cells, red blood cells, platelets) obtained after the blood salts thereof. sample was diluted with a blood diluent according to the 5. The blood diluent according to claim 1, wherein said at present disclosure and stored for 2 hours, are substantially the least one purine compound or salt thereof are in a concentra same as those curves obtained from a sample analyzed only tion ranging from approximately 0.05 g/L to approximately 5-minutes after collection. 25 g/L. 0061 FIGS. 5 and 6 correspond to examples 4 and 5, 6. The blood diluent according to claim 1, wherein said at respectively, wherein caffeine is used and the pH values of the least one purine compound or salt thereof are in a concentra blood diluent as used are pH 5.0 and pH 9.5 respectively. It tion ranging from approximately 0.3 g/L to approximately 10 can be seen from FIGS. 5 and 6 that blood diluents prepared g/L. according to the present disclosure with a pH of approxi 7. The blood diluent according to claim 1, wherein said at mately 5.0 and 9.5 can both effectively stabilize the blood least one purine compound or salt thereof are in a concentra samples beyond 2 hours after collection. tion of approximately 0.5 g/L. 8. The blood diluent according to claim 2, wherein said at 0062 FIGS. 7-11 correspond to examples 6-10, respec least one alkali metal salt is selected from alkali metal sulfates tively, wherein aminophylline, theophylline, uric acid, caf and alkali metal halides. feine and hypoxanthine are used, and to comparative 9. The blood diluent according to claim 2, wherein said examples 1-5 wherein N-(2-acetamido)-2-iminodiacetic acid blood diluent has a conductivity ranging from approximately (ADA), dimethylurea and (2-pyridinethiol-1-oxide) sodium 16 mS/cm to approximately 22 mS/cm and an osmotic pres are used. Examples 6-10 and comparative examples 1-5 are Sure ranging from approximately 250 mOsm/Kg to approxi used as stability tests of a blood diluent prepared according to mately 350 mOsm/Kg. the present disclosure. It can be seen from the figures that the 10. The blood diluent according to claim 2, wherein said at blood diluents of examples 6-10 can effectively stabilize the least one organic buffers and/or at least one inorganic buffers blood components in the blood sample for a period of time are selected from the group consisting of formic acid, phthalic (FIG. 7, 2 hours and 33 minutes: FIG. 8, 2 hours and 3 acid, acetic acid, phosphoric acid, TRIS, boric acid, carbonic minutes: FIG.9, 3 hours; FIG. 10,3 hours and 30 minutes and acid and salts thereof and combinations thereof. FIG. 11, 2hours and 5 minutes). In contrast, the histograms of 11. The blood diluent according to claim 2, wherein said comparative examples 1-5 for white blood cells change con blood diluent has a pH value ranging from approximately 5.0 siderably during the same time. to approximately 9.5. 0063. It is understood from the above specific embodi 12. The blood diluent according to claim 2, wherein said ments that the various embodiments of blood diluents accord blood components are selected from red blood cells, white ing to the present disclosure can effectively stabilize red blood cells, platelets and hemoglobin. blood cells, white blood cells in the blood sample for at least 13. A method for analyzing blood components, said 2, giving satisfactory results on a blood cell analyzers. method comprising the step of mixing the blood sample with 0064. It will be understood by those having skill in the art the blood diluent of claim 1 and at least one lysing agent. that many changes may be made to the details of the above 14. A method for analyzing blood components, said described embodiments without departing from the underly method comprising the step of mixing the blood sample with ing principles of the invention. The scope of the present the blood diluent of claim 2 and at least one lysing agent. invention should, therefore, be determined only by the fol lowing claims. c c c c c