犬貓貧血的實(shí)驗(yàn)室診斷

1、犬貓貧血的實(shí)驗(yàn)室診斷講座二 貧血的實(shí)驗(yàn)室診斷 原著 Professor Michael J. Day 翻譯：劉睿 獸醫(yī)師（廣州） ,校對(duì)：戴庶 獸醫(yī)師（廣州）、八雖然大部分的檢測(cè) 在使用儀器檢測(cè) 也包括血涂片檢查前言 如果要對(duì)貧血?jiǎng)游镒龀龀晒Φ脑\斷和管理, 不可或缺一定水準(zhǔn)的實(shí)驗(yàn)室檢查。 血液學(xué)檢查可 在院內(nèi)做；或保存為 EDTA抗凝血后，送檢至商業(yè)診斷實(shí)驗(yàn)室。要進(jìn)行基本的血液分析，最 低限度的實(shí)驗(yàn)室設(shè)備應(yīng)包括： 微量血細(xì)胞比容法離心機(jī)和毛細(xì)管判讀器、 制備染色血涂片的 材料、用于評(píng)估血涂片所用的顯微鏡。準(zhǔn)備一臺(tái)折射儀來測(cè)定血漿蛋白含量也是有價(jià)值的。 如今,臨床實(shí)驗(yàn)室已經(jīng)有條件使用日趨精密的檢

2、測(cè)設(shè)備來進(jìn)行血液分析。 設(shè)備能夠獲得可信的紅細(xì)胞和白細(xì)胞數(shù)據(jù), 但血小板的檢測(cè)值可能被低估。 血樣的同時(shí), 應(yīng)配合血涂片鏡檢。 本講座回顧了紅細(xì)胞參數(shù)的相關(guān)知識(shí), 中可能遇見的各種紅細(xì)胞形態(tài)學(xué)改變情況。紅細(xì)胞參數(shù)通過離心微量HcT）通過自或血細(xì)胞計(jì)紅細(xì)胞計(jì)數(shù)，PCV和Hb 紅細(xì)胞壓積（PCV是指紅細(xì)胞總數(shù)（RBCs所占全血中的體積比。PCV測(cè)量：紅細(xì)胞壓積管后，人工判讀數(shù)據(jù)，并記錄為占血液總量百分比。血細(xì)胞壓積（ 動(dòng)血液分析儀在細(xì)胞大小和數(shù)量的基礎(chǔ)上判定。 紅細(xì)胞總數(shù)可使用自動(dòng)化儀器， 數(shù)器在鏡下計(jì)數(shù)來獲得，用RBC X 1012/1表示。血液中的血紅蛋白（Hb）含量同樣也可以使用自動(dòng)化儀器判

3、定，記錄為 g/dl。Hb （血紅蛋 白）的含量測(cè)定受血液樣本中存在脂血癥、 紅細(xì)胞溶解癥或膽紅素血的影響。 一個(gè)檢驗(yàn)結(jié)果 精確性的簡(jiǎn)單方法：3 X Hb= Ht （血細(xì)胞壓積）。檢測(cè)到的數(shù)值要參照 “正常范圍值” 來比較， 但要明確“正常范圍值” 并不適用于所有情況。 舉例來說，初生或者懷孕動(dòng)物可能會(huì)呈現(xiàn)數(shù)值偏差，并且某些動(dòng)物也存在品種效應(yīng)（例如， 視覺獵犬（sight hounds）就呈現(xiàn)高PCV值和低嗜中性粒細(xì)胞計(jì)數(shù)）。PCV, RBC計(jì)數(shù)和HB都 反映了紅細(xì)胞質(zhì)量，并且這三個(gè)參數(shù)之間通常具有相關(guān)性，所以簡(jiǎn)單的測(cè)定PCV值即是一個(gè)良好的臨床指征。中度貧血 18-29%，重度貧血 18%。

4、 中度貧血 15-19%，重度貧血 60 X 109/表示顯著的再生。RPD也可能需要確定。RPI對(duì)“校正”貧血程度集結(jié)狀網(wǎng)織紅細(xì)胞，但貓二者都有。在犬上， 網(wǎng)織紅細(xì)胞百分比 （在紅細(xì)胞中） X 109/l 是再生性貧血反應(yīng)的象征， 400 作為另外一個(gè)選擇，網(wǎng)織紅細(xì)胞生成指數(shù)（ 的評(píng)估和網(wǎng)織紅細(xì)胞壽命有重要價(jià)值。1 ）貧血程度校正校正值% （或計(jì)數(shù)值）=絕對(duì)值% （或計(jì)數(shù)值）X PCV值/正常PCV值（45） 2）網(wǎng)織紅細(xì)胞壽命校正RPI = 校正值 % X 1/血液成熟時(shí)間 血液成熟時(shí)間取決于 PCV值：PCV45%1 天35%1.5 天25%2 天15%2.5 天RPI 2.5時(shí)，表示再

5、生性貧血反應(yīng)。貓集結(jié)狀網(wǎng)織紅細(xì)胞最初從骨髓中被釋放， 在經(jīng)過 10-12 天的成熟期后， 轉(zhuǎn)變?yōu)辄c(diǎn)狀網(wǎng)織紅 細(xì)胞。 相比之下，點(diǎn)狀網(wǎng)織紅細(xì)胞在循環(huán)血液中出現(xiàn)需要 3-4 周。在貓上，集結(jié)狀網(wǎng)織紅 細(xì)胞計(jì)數(shù)可判定再生性貧血， 它反映骨髓再生活躍程度， 而點(diǎn)狀紅細(xì)胞計(jì)數(shù)代表累積再生貧 血。集結(jié)狀紅細(xì)胞計(jì)數(shù) 40 X 109/l 表示再生性貧血， 200 X 109/l 時(shí)表示顯著再生性貧血。而后一種樣本給 但要獲得優(yōu)質(zhì)的穿 通常在股骨干骨髓評(píng)估 對(duì)于非再生性貧血的病例，骨髓評(píng)估是診斷過程的一個(gè)重要步驟?？赡苄枰杉瘍煞N樣本： 抽取骨髓內(nèi)容物或用骨髓針穿刺活檢。 前一種樣本給臨床病理學(xué)專家分析， 組

6、織病理學(xué)專家分析。 骨髓穿刺針的優(yōu)點(diǎn)是病理組織可得到更好的評(píng)估， 刺活檢物卻具有挑戰(zhàn)性。 將穿刺活檢物放入福爾馬林溶液固定之前先做壓片。骨（貓）或髂骨嵴（犬）來獲得樣本。在大型犬，肋骨或胸骨節(jié)是骨髓抽取的備用位置。抽取的骨髓樣本應(yīng)放入 EDTA或ACD （可從采血袋中獲得）抗凝血?jiǎng)┲斜４?，同時(shí)至少要制備 10 張壓片， 迅速空氣干燥后染色。 主要的譜系細(xì)胞應(yīng)該按照成熟程度、 所占的相對(duì)比例、 粒細(xì)胞和紅細(xì)胞比例的順序依次確定。同時(shí)應(yīng)該檢測(cè)異常細(xì)胞（腫瘤細(xì)胞）LECTURE 2. LABORATORY DIAGNOSIS OF ANAEMIAINTRODUCTIONThe anaemic pat

7、ient cannot be successfully diagnosed and managed without at least some level of laboratory testing. This may be undertaken in-practice or by sending EDTA anticoagulated blood to a commercial diagnostic laboratory. The minimum in-practice equipment required for basic haematological analysis would be

8、 a microhaematocrit centrifuge and tube reader, materials for preparation of a stained blood smear and a microscope for evaluation of the blood smear. A refractometer for assessment of plasma proteins is also valuable.Increasingly sophisticated instrumentation is now available for in-practice labora

9、tories to undertake haematological analysis. Most of these machines produce acceptable data for red and white blood cells but may underestimate platelets. It is essential to examine a blood smear in parallel with assessing the readings from such equipment. This lecture reviews the erythrocyte parame

10、ters and cytological changes that may be seen on examination of the blood smear.ERYTHROCYTE PARAMETERSTotal red blood cell count, PCV and HbThe packed cell volume (PCV) is the percentage of blood volume made up of red blood cells (RBCs). It is determined manually by centrifugation of a microhaematoc

11、rit tube and recorded as a percentage of blood volume. The haematocrit (Hct) is determined by the automated haematology analyser on the basis of cell size and number. The total RBC count is determined in automated fashion or may be measured manually using a haemocytometer chamber and microscope. Thi

12、s parameter is recorded as RBC X 101/2l. The concentration of haemoglobin (Hb) in the blood is also determined in automated fashion and reported as g/dl. Determination of Hb concentration will be affected by the presence of lipaemia, haemolysis or bilirubin in the blood sample. A simple check for ac

13、curacy is that the HbX 3 should equal the haematocrit.These values are assessed relative to a normal reference range but it should be remembered that these reference ranges may not apply to all situations. For example very young animals or pregnant animals may have outlying values and there are some

14、 breed-related effects (e.g. sight hounds have relatively high PCV and lower neutrophil count). The PCV, RBC count and Hb all reflect the red cell mass and these three parameters generally correlate, so simple PCV measurement is a good index to use.The PCV may be used to describe the severity of ana

15、emia. As an approximation a doghas a mild an aemia with a PCV of 30 -36%, moderate an aemia at 18 -29% and severe an aemia at 18%. A cat has mild anaemia at 20 - 24%, moderate anaemia at 15 - 19% and severe anaemia at 60 a count of 400 X109/l indicates markedproduction index (RPI) may be determined.

16、 anaemia and the lifespan of the reticulocyte. is calculated by:Corrected % (or count) = observed % (or count) The second correction is for reticulocyte lifespan:In the dog the percentage reticulocytes (of red cells) should be expressed as an absolute X109/l is indicative of a regenerative response

17、and regeneration. Alternatively, the reticulocyte The RPI correctsthecount for the degree of The first correction is for degree of anaemia thatX observed PCV/normal PCV (45)45%1 day35%1.5 days25%2 days15%2.5 daysRPI = corrected % /bloxod 1maturation time where maturation time depends upon the PCV: P

18、CVAn RPI 2.5 indicates a regenerative anaemia.Feline aggregate reticulocytes are recent marrow emigrants that become punctate reticulocytes after a 10 -12 day maturation time. By contrast, punctate reticulocytes have been present in the circulation for 3 - 4 weeks. Aggregate reticulocytes should be

19、counted to determine regeneration in the cat as they represent active bone marrow regeneration whereas pun ctate forms rep rese nt cumulative rege nerati on.An aggregate count of 40x 109/1 in dicatesrege nerati on and of 200x 109/l in dicates marked rege nerati on.BONE MARROW EVALUATIONFor non-regen

20、erative anaemia evaluation of the bone marrow is an important part of the diagnostic process. Two sample types may be collected: an aspirate of medullary content or a bone marrow needle core biopsy. The former sample is evaluated by the clinical pathologist and the latter by a histopathologist.The advantage of core biopsy is that the tissue pathologymay be better evaluated, but