The rabbit test, or Friedman test, was an early

pregnancy test A pregnancy test is used to determine whether a female is pregnant or not. The two primary methods are testing for the female pregnancy hormone (human chorionic gonadotropin (hCG)) in blood or urine using a pregnancy test kit, and scanning with ...

developed in 1931 by Maurice Friedman and Maxwell Edward Lapham at the

University of Pennsylvania The University of Pennsylvania (also known as Penn or UPenn) is a private research university in Philadelphia. It is the fourth-oldest institution of higher education in the United States and is ranked among the highest-regarded universitie ...

Test

The hormone

human chorionic gonadotropin Human chorionic gonadotropin (hCG) is a hormone for the maternal recognition of pregnancy produced by trophoblast cells that are surrounding a growing embryo (syncytiotrophoblast initially), which eventually forms the placenta after implantatio ...

(hCG) is produced during

pregnancy Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

and can be found in a pregnant woman's

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

and blood; it indicates the presence of an implanted fertilized egg. An earlier test, known as the AZ test, was developed by Selmar Aschheim and

Bernhard Zondek Bernhard Zondek ( he, ברנרד צונדק; 29 July 1891 – 8 November 1966) was a German-born Israeli gynecologist who developed the first reliable pregnancy test in 1928. Biography Bernhard Zondek was born in Wronke, Germany, now Wronki, Po ...

. When urine from a woman in the early months of

was injected into immature female mice, their

ovaries The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...

would enlarge and show follicular maturation. The test was considered reliable, with an error rate of less than 2%. Friedman and Lapham's test was essentially identical, but replaced the mouse with a rabbit. A few days after the injection, the animal would be

dissected Dissection (from Latin ' "to cut to pieces"; also called anatomization) is the dismembering of the body of a deceased animal or plant to study its anatomical structure. Autopsy is used in pathology and forensic medicine to determine the cause ...

and the size of her ovaries examined. The rabbit test became a widely used

bioassay A bioassay is an analytical method to determine the concentration or potency of a substance by its effect on living animals or plants (''in vivo''), or on living cells or tissues(''in vitro''). A bioassay can be either quantal or quantitative, dir ...

(animal-based test) to test for pregnancy. The term "rabbit test" was first recorded in 1949, and was the origin of a common euphemism, "the rabbit died", for a positive pregnancy test. The phrase was, in fact, based on a common misconception about the test. While many people assumed that the injected rabbit would die only if the woman was pregnant, in fact all rabbits used for the test died, as they had to be dissected in order to examine the ovaries. A later alternative to the rabbit test, known as the " Hogben test", used the

African clawed frog The African clawed frog (''Xenopus laevis'', also known as the xenopus, African clawed toad, African claw-toed frog or the ''platanna'') is a species of African aquatic frog of the family Pipidae. Its name is derived from the three short claws o ...

, and yielded results without the need to cut the animal open. Modern

s continue to operate on the basis of testing for the presence of the hormone hCG in the blood or urine, but no longer require the use of a live animal.

References

Sources

External links

*
The Rabbit Test
at

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About dot Com Explanation
at German Inventions and Discoveries
The demand for pregnancy testing: The Aschheim–Zondek reaction, diagnostic versatility, and laboratory services in 1930s Britain, pages 240–241
{{DEFAULTSORT:Rabbit Test Tests for pregnancy *