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11 Cards in this Set
- Front
- Back
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hcg conc during pregnancy |
Large increase at the start of pregnancy and then sustained thoughtout pregnancy at lower levels |
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Pregnancy is associated with an increase in blood and urine levels off |
HCG (human chorioni gondatropin) Estrogen Progesterone |
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How did HCG form the basis of pregnancy testing |
Historically serum would be taken from women and injected into a rabbit and if HCG was present ovulation would occur |
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HCG was cloned and antibodies raised to it allowing the development of immunoassays What are the 3 main types |
Inhibition of latex agglutination Radioimmunoassay Dip stick- home |
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What is inhibition of latex agglutination |
rabbit anti -hcg is mixed with serum sample If hcg is oresent it will be bound and remove the anti-hcg beads so they cant react with further reactions Latex beads coated with hcg are added to the sample Agglutination- negative No agglutination- positive pregnant |
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Radio immunoassay for HCG |
Rabbit anti-HCG is mixed with serum sample If HCG is present it will be bound and remove anti-HCG from further reactions Radiolabelled HCG is added Highly radioactive- not pregnant Not radioactive- pregnant |
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Explain a dip stick reaction |
Rabbit anti- HCG is bound to coloured latex beads and dried onto filter paper, Mix with urine, HCG is present it will be bound by ab. If hcg is not present it wont be bound. The latex beads travel up the filter paper where they pass a line of immobilised ANTI-HCG. if HCG IS present on the latex beads they will be bound by ab and form a line. Some latex beads travel further up the filter paper and pass a line of immobilised anti-rabbit IgG- they are bound by ab and the beads stop and form a line as a positive control |
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Adv and disadvantages of inhibition of latex agglutination (ILA) |
Time consuming snd realise on visual interpretation Not absolutely quantitiative |
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Adv and disadvantages of RIA |
Easily automated Is easily quantified Produces radioactive wastes |
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Adv and disadv of dipsticks |
Very simple Not quantitative |
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What are some problems in measuring HCG |
Raised in other rare conditions such as tumours Also raised if incomplete abortion Is not present in ectopic pregnancy |
