引言
血球計(jì)數(shù)板一直是實(shí)驗(yàn)室細(xì)胞計(jì)數(shù)的金牌標(biāo)準(zhǔn)。自從18世紀(jì)在法國(guó)第一次被用于分析病人的血液樣本,血球計(jì)數(shù)板在過(guò)去幾百年中已經(jīng)得到一系列的重大發(fā)展,相比以前計(jì)數(shù)更為精確、使用更為簡(jiǎn)單,并最終形成了今天我們使用的樣子?,F(xiàn)在血球計(jì)數(shù)板計(jì)數(shù)仍然是所有細(xì)胞學(xué)研究的一個(gè)組成部分,然而其計(jì)數(shù)存在的問(wèn)題由于自身固有的設(shè)計(jì)和使用方法并沒(méi)有隨著時(shí)間而消失。我們?cè)谶@里將要列出造成血球計(jì)數(shù)板計(jì)數(shù)誤差的來(lái)源, 并將討論自動(dòng)化計(jì)數(shù)是如何消除這些問(wèn)題的。
血球計(jì)數(shù)板計(jì)數(shù)誤差的來(lái)源
1. 人工失誤(混勻、加樣、稀釋、計(jì)算錯(cuò)誤以及人工操作誤差)
a. 在對(duì)5個(gè)操作者的觀察中,操作錯(cuò)誤和隨機(jī)錯(cuò)誤分別占3.12%和7.8%[3]。
b. James M. Ramsey做了一項(xiàng)實(shí)驗(yàn),衡量取樣區(qū)和稀釋系數(shù)如何影響計(jì)數(shù)的準(zhǔn)確性。
他測(cè)試了3個(gè)取樣區(qū)面積(18, 9和4 mm2)及兩個(gè)稀釋系數(shù)(1:100 和 1:25)。取樣面積減小時(shí)CVs值是升高的,稀釋倍數(shù)的升高會(huì)降低CVs[4]。
c. Bane 發(fā)現(xiàn),當(dāng)同一個(gè)操作者去對(duì)同樣的兩份精液樣品計(jì)數(shù)時(shí),計(jì)數(shù)結(jié)果的差異55%歸因于取樣和移液?jiǎn)栴}, 45%歸因于計(jì)數(shù)室和細(xì)胞計(jì)數(shù)問(wèn)題 [5]。 Freund和Carol 展開(kāi)的另外一項(xiàng)實(shí)驗(yàn)表明,不同操作者之間的計(jì)數(shù)差異能高達(dá)52%,而同一個(gè)操作者的計(jì)數(shù)差異為20%[5]。
2. 多次計(jì)數(shù)以保證結(jié)果準(zhǔn)確性的必要性
a. 1907年, John C. DaCosta 聲明,為了得到精確的計(jì)數(shù)結(jié)果,很有必要取血液樣品中的多滴血液分別進(jìn)行計(jì)數(shù)[1]。
b. Nielsen, Smyth和Greenfield得出結(jié)論, 為了得到10%, 15%和 20%的血球計(jì)數(shù)板計(jì)數(shù)準(zhǔn)確性, ,必需的樣品數(shù)分別為7份, 3份和2份,每份樣品中分別包含180個(gè), 200個(gè)和125個(gè)細(xì)胞[6]。
c. 1881年, Lyon 和Thoma推測(cè)血球計(jì)數(shù)板的標(biāo)準(zhǔn)誤差為 ,其中n即計(jì)數(shù)的細(xì)胞數(shù)目。
d. 1907年, William Sealy以“學(xué)生”的名義發(fā)布了他計(jì)數(shù)釀啤酒師的酵母的工作,他特地通過(guò)實(shí)驗(yàn)和數(shù)學(xué)模型計(jì)算了計(jì)數(shù)誤差,公式也為[7,8]。
3. 細(xì)胞均勻分布的要求
a. 1912年, James C. Todd將細(xì)胞分布不均勻列為計(jì)數(shù)誤差的問(wèn)題來(lái)源[1]。
b. 學(xué)生也說(shuō)有兩項(xiàng)主要的計(jì)數(shù)誤差來(lái)源,一為吸取的酵母樣品不能夠代表原液的濃度,另一個(gè)是隨機(jī)取樣時(shí)細(xì)胞在計(jì)數(shù)區(qū)域分布不均勻[7,8]。
c. 1947年, 一篇文章提到血球計(jì)數(shù)板中的細(xì)胞濃度分布不均勻問(wèn)題。初布的結(jié)果顯示,離進(jìn)樣口的濃度分別比平均濃度低3.5%和高3.5%[9]。
4. 儀器及材料差異(柵格,深度,蓋玻片,緩沖液類型以及移液器)
a. 結(jié)果顯示計(jì)數(shù)室的計(jì)數(shù)誤差和移液器(CV%)造成的計(jì)數(shù)誤差分別在大約4.6% 和4.7%[10]。
b. 在一項(xiàng)5個(gè)計(jì)數(shù)人員的計(jì)數(shù)實(shí)驗(yàn)中,移液器和血細(xì)胞計(jì)數(shù)器造成的誤差分別為9.46% 和4.26%[3]。
c. 1961年, Sanders和Skerry得出結(jié)論,蓋玻片的位置能造成7.6%的計(jì)數(shù)差異[11]。
d. 在關(guān)于不同稀釋步驟的計(jì)數(shù)實(shí)驗(yàn)中,隨著稀釋步驟的增加,變異系數(shù)升高,每個(gè)血細(xì)胞計(jì)數(shù)系統(tǒng)的誤差如下: Bürker-Türk (BT) (7.7%-12%), Thoma (6.6%-14.1%), Makler (19.8%-23.6%)[12]。
解決血球計(jì)數(shù)板的計(jì)數(shù)問(wèn)題
隨著新技術(shù)的發(fā)展,如計(jì)算機(jī)技術(shù)、自動(dòng)化軟件、光學(xué)鏡片、熒光染料、精密制造,以及現(xiàn)代技術(shù)如熒光顯微技術(shù)、流式細(xì)胞術(shù)、圖像細(xì)胞術(shù),自動(dòng)化已經(jīng)解決了血球計(jì)數(shù)板存在的許多問(wèn)題[13-25]。
自動(dòng)化計(jì)數(shù)解決:
人工操作誤差 - 為了解決這個(gè)問(wèn)題,自動(dòng)化和機(jī)器人技術(shù)能夠代替人工的樣品操作和計(jì)數(shù)操作。
加樣誤差 - 取樣區(qū)越多、計(jì)數(shù)細(xì)胞越多,隨機(jī)誤差越小,但是需要時(shí)間越多。通過(guò)應(yīng)用自動(dòng)取樣或者成像技術(shù),成千上百萬(wàn)的細(xì)胞能在很短時(shí)間內(nèi)被分析,提高了效率,并把分析中的隨機(jī)誤差降到更低。
移液和稀釋誤差 - 這些取決于操作者的操作經(jīng)驗(yàn)。通過(guò)采用自動(dòng)加樣器或者自動(dòng)液流系統(tǒng),這個(gè)誤差可以被降到更低[26]。
材料誤差 - 計(jì)數(shù)室的誤差是由于不同品牌的血球計(jì)數(shù)板或者同一品牌不同批次間的差異造成的。這也可以通過(guò)自動(dòng)細(xì)胞計(jì)數(shù)儀(細(xì)胞計(jì)數(shù)儀的選擇,請(qǐng)查閱 http://dakewe.com/product/view/id-71.html 或百度文庫(kù) http://wenku.baidu.com/view/f13faf4916fc700abb68fc54.html 中《細(xì)胞計(jì)數(shù)儀的選擇》一文)增加取樣量及減小隨機(jī)誤差來(lái)解決。
細(xì)胞分布不均勻 – 血球計(jì)數(shù)板不合適的清洗,或者蓋玻片放置不正確將會(huì)產(chǎn)生誤差。這些可以通過(guò)不使用計(jì)數(shù)室的細(xì)胞計(jì)數(shù)儀來(lái)消除,比如流式細(xì)胞儀。但是細(xì)胞樣品中若是存在細(xì)胞團(tuán),基于液流計(jì)數(shù)的儀器將很難計(jì)數(shù),而使用圖像計(jì)數(shù)儀,細(xì)胞團(tuán)可以使用圖像分析算法計(jì)數(shù)聚集的細(xì)胞,這樣可以提高細(xì)胞計(jì)數(shù)的準(zhǔn)確性。
綜述
血球計(jì)數(shù)板幾百年來(lái)在生物醫(yī)學(xué)研究中一直都是一個(gè)必備的工具,并且經(jīng)歷了很多的改進(jìn)形成了今天研究者們使用的樣子,然而它仍然會(huì)造成很多不可避免的計(jì)數(shù)誤差。今天,現(xiàn)代化的自動(dòng)細(xì)胞計(jì)數(shù)儀的使用已經(jīng)很大程度上消除了許多出現(xiàn)誤差的來(lái)源,提高了細(xì)胞計(jì)數(shù)的準(zhǔn)確性和效率。
參閱文獻(xiàn)
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