en>Banaphshu: /* 15-limit */ added alternative lattice for 15 limit diamond

2015-01-11T23:58:02Z

15-limit: added alternative lattice for 15 limit diamond

en>Hyacinth: /* References */ {{Harry Partch}}

2013-10-23T19:34:36Z

References: {{Harry Partch}}

← Older revision		Revision as of 21:34, 23 October 2013
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	~~Emilia Shryock~~ is my name but ~~you~~ can ~~contact me something you like~~. ~~Hiring~~ is ~~his occupation~~. ~~One~~ of the ~~things she enjoys most~~ is to ~~read comics~~ and ~~she'll~~ be ~~beginning some thing else along~~ with it~~. Her family lives~~ in ~~Minnesota.~~<br><br>~~My web~~-~~site~~ ... ~~std testing at home (~~[http://~~vei~~.~~cuaed~~.~~unam~~.mx/es/~~node~~/~~4882 relevant web page~~])		[[File:Kleihauer.JPG\|thumb\|right\|thumb\|Kleihauer test, showing fetal red blood cells in rose-pink color, while adult red blood cells are only seen as "ghosts".]]
			The '''Kleihauer–Betke ("KB") test''', '''Kleihauer–Betke ("KB") stain''' or '''Kleihauer test''', is a [[blood test]] used to measure the amount of [[fetal hemoglobin]] transferred from a [[fetus]] to a mother's [[bloodstream]].<ref name="pmid17191260">
			{{cite journal
			\|author=Katiyar R, Kriplani A, Agarwal N, Bhatla N, Kabra M
			\|title=Detection of fetomaternal hemorrhage following chorionic villus sampling by Kleihauer–Betke test and rise in maternal serum alpha feto protein
			\|journal=Prenat. Diagn.
			\|volume=27
			\|issue=2
			\|pages=139–42
			\|year=2007
			\|pmid=17191260
			\|doi=10.1002/pd.1632
			\|accessdate=2007-08-17}}</ref> It is usually performed on [[Rhesus blood group system\|Rhesus-negative]] mothers to determine the required dose of [[Rho(D) immune globulin]] (RhIg) to inhibit formation of Rh [[antibody\|antibodies]] in the mother and prevent [[Rh disease]] in future Rh-positive children.<ref name="pmid22231030">{{cite journal \|author=Kim YA, Makar RS \|title=Detection of fetomaternal hemorrhage \|journal=American Journal of Hematology \|volume=87 \|issue=4 \|pages=417–23 \|date=April 2012 \|pmid=22231030 \|doi=10.1002/ajh.22255 \|url=}}</ref>

			==Test details==
			The KB test is the standard method of quantitating [[fetal-maternal hemorrhage]] (FMH). It takes advantage of the differential resistance of fetal hemoglobin to acid. A standard [[blood smear]] is prepared from the mother's [[blood]], and exposed to an acid bath. This removes adult [[hemoglobin]], but not fetal hemoglobin, from the red blood cells. Subsequent staining, using Shepard's method,<ref>Alcoholic haematoxylin, acidified ferric chloride, Shepard's counterstain. Shepard's Fixative/Diluent</ref> makes fetal cells (containing fetal hemoglobin) appear rose-pink in color, while adult red blood cells are only seen as "ghosts". 2000 cells are counted under the microscope and a percentage of fetal to maternal cells is calculated.

			In those with positive tests, follow up testing at a [[postpartum]] check should be done to rule out the possibility of a [[false positive]]. This could be caused by a process in the mother which causes persistent elevation of fetal hemoglobin, e.g. [[sickle cell trait]].

			Comparison with other more expensive or technologically advanced methods such as [[flow cytometry]] has shown that the KB stain, like the more advanced methods, is sensitive in its detection of FMH.<ref name="pmid17191260" /> Background counting errors can result in estimates of as much as 5 ml fetal [[blood loss]] when there actually is no such blood loss, but standard methods available in most laboratories admit an extremely low probability of the return of a false positive when more severe FMH has taken place.

			==Uses==

			===Fetal–maternal hemorrhage severity estimation===
			To determine if a positive test for FMH should be considered as the likely cause of fetal death, the percent of total fetal blood volume lost should be calculated, making appropriate adjustments based on the following known relationships:
			** the size of a fetal red blood cell is 1.22 times that of an adult red blood cell;
			** the KB stain is known to have a [[mean]] success rate of 92% in detecting fetal red blood cells;
			** in a woman at or near term in her pregnancy, the mean volume of maternal red blood cells is approximately 1800 ml;
			** the mean fetal [[hematocrit]] is 50%; and
			** at [[stillbirth]], the mean fetal blood volume is <math>150 \frac{ml}{kg}</math>
			These [[Constraint (mathematics)\|constraint]]s can then be applied to yield the formula

			<center><math>PFB = \frac{(3200)(FC)}{(FW)(MC)}</math></center>

			where
			** <math>PFB</math> is the percentage of fetal blood lost;
			** <math>FC</math> is the observed number of fetal red blood cells;
			** <math>MC</math> is the observed number of maternal red blood cells (N.B. we have that <math>MC = TC - FC</math>, where <math>TC</math> is the total observed number of red blood cells, both maternal and fetal);
			** <math>FW</math> is the stillbirth weight of the fetus in kilograms.

			===Stillbirth resolution===
			Suppose that a KB stain is performed and <math>TC = 5000</math> total red blood cells are observed, <math>FC = 200</math> of which are found to be fetal red blood cells. Suppose further that the stillbirth weight of the fetus under consideration is <math>FW = 2.0 kg</math>. Then we would conclude that the total percentage of fetal blood lost is approximately

			<center><math>PFB = \frac{(3200)(FC)}{(FW)(MC)} = \frac{(3200)(200)}{(2.0)(4800)} = \frac{200}{3} = 66.667</math></center>

			to five [[significant digits]]. We would hence conclude that the fetus under consideration lost 66.667% (two-thirds) of its blood via FMH. Generally, stillbirth is highly probable for any value of <math>PFB \geq 20</math>, particularly if the fetus abruptly loses this much blood; in this example, we would hence be likely to suspect FMH as the cause of the stillbirth. It is important to note, however, that such a [[diagnosis]] is still not completely conclusive; fetuses losing large quantities of blood over long periods of time are able to compensate for this slower blood loss; since the KB stain tells us nothing with regard to the level of acuity of FMH. This means that it is not possible to entirely correlate a positive KB stain and high <math>PFB</math> with a stillbirth, though in many cases, given other information, such as known hereditary complications of pregnancy, extremely high positive [[Pearson product-moment correlation coefficient\|correlation coefficients]] <math>r \approx +1.000</math> between FMH and stillbirth have been observed.

			== Fetal red-blood-cell detection problems ==

			Since fetal and maternal [[blood cell]]s have the same life expectancy in the maternal bloodstream, it is possible to obtain informative results from a KB stain for a fair period of time after a stillbirth. However, if the mother and fetus are [[Blood type\|ABO]] incompatible, it is more crucial to quickly perform the KB stain following a stillbirth, as the fetal red blood cells will be eliminated from the maternal bloodstream very quickly, causing the KB stain to underestimate the degree of FMH, if any.

			Lots of concern has been raised in the literature concerning false positives when sampling is done after delivery. In general this is not a problem. Delivery does result in higher frequency of detection of micro-hemorrhages but this should not confound interpretation of FMH as a possible cause of stillbirth. It is not necessary to draw the sample before induction, onset of labor, delivery, placental delivery etc. despite what some published literature purports. However, if caesarean section is to be used, failure to draw the sample prior to that will result in a 2% false positive rate.

			Finally, anything which causes persistence of fetal hemoglobin in maternal blood cells will make interpretation much trickier. Certain [[hemoglobinopathy\|hemoglobinopathies]], the most common of which is sickle cell trait, do this. Overall, somewhere around 1–3% of the time this could result in false interpretation.

			== See also ==

			*[[Apt test]]

			==External links==
			* [http://www.kemh.health.wa.gov.au/development/manuals/O&G_guidelines/sectiona/1/a1.9.2.pdf] The Kleihauer Test,
			King Edward Memorial Hospital,Perth Western Australia

			== References ==

			{{reflist}}
			{{Myeloid blood tests}}
			{{Obstetrical procedures}}

			{{DEFAULTSORT:Kleihauer-Betke Test}}
			[[Category:Blood tests]]
			[[Category:Tests during pregnancy]]

en>The1337gamer at 12:10, 31 May 2012

2012-05-31T12:10:52Z

New page

Emilia Shryock is my name but you can contact me something you like. Hiring is his occupation. One of the things she enjoys most is to read comics and she'll be beginning some thing else along with it. Her family lives in Minnesota.<br><br>My web-site ... std testing at home ([http://vei.cuaed.unam.mx/es/node/4882 relevant web page])

Tonality diamond - Revision history

en>Banaphshu: /* 15-limit */ added alternative lattice for 15 limit diamond

en>Hyacinth: /* References */ {{Harry Partch}}

en>The1337gamer at 12:10, 31 May 2012