tests Flashcards
(43 cards)
causes of false positive syphilis (non-treponemal) test
detects antibodies to cardiolipin-cholesterol-lecithin SO Autoimmune diseases such as SLE, rheumatoid arthritis, and antiphospholipid syndrome (APS).
Endocarditis
Infections, pregnancy, IV drug use, tuberculosis, chronic liver disease, recent vaccines.
maximum level of progesterone is found at what stage of pregnancy
term
body ache, malaise. only abnormal blood test is raised ALP (and not pregnant). What is the diagnosis?
Vitamin D deficiency
What is the name of the thermostable DNA polymerase extracted from the thermophilic bacteria Thermus aquaticus, widely used in the polymerase chain reaction (PCR) technique for amplifying specific DNA sequences?
taq polymerase
(from ‘Thermus AQuaticus’)
daily sperm production
300 million
how to calculate number needed to treat
1 / absolute risk ratio
(ARR = %control event ratio - %experimental event ratio)
how do you calculate the interquartile range?
third quartile minus first quartile
Q3 - Q1
what is variance?
The variance is a figure that represents how far the data in your sample is clustered around the mean
It is calculated from sum of squares / (n-1)
(sum of squares = sum ((each value - mean)^2))
how to calculate standard deviation from variance
sd = square root of the variance
T4:T3 ratio secreted from the healthy human thyroid gland is…
approximately 15:1
elevated LDH in which ovarian cancer
ovarian dysgerminoma
how to detect syphilis from chancre
dark field microscopy or direct fluorescent antibody
because they haven’t seroconverted yet so the blood tests may be negative
are VDRL and RPR treponemal or non-treponemal
non-treponemal
thus non-specific (can get false +)
but are very sensitive
and titres go down with treatment
the treponemal tests tend to have T in them.
The exceptions are CIA (treponemal)
and TRUST (non-treponemal)
which tests for syphilis are positive for life once infected? Treponemal or non-treponemal
Treponemal positive for life
non-treponemal go up and down. Titres can be used to see if adequate treatment (4-fold decrease in titre)
when might you get a false NEGATIVE non-treponemal test for syphilis?
latent syphilis
very early syphilis
what should you do if you get a positive screening test (treponemal EIA/CLIA or RPR) for syphilis
confirmatory second test with either TPHA/TPLA or a second EIA/CLIA
positive treponemal test
negative non-treponemal test
previously treated syphilis
or latent syphilis
or false positive (so should repeat treponemal test)
negative treponemal test
positive non-treponemal test
false positive non-treponemal e.g. Lupus, RA, antiphospholipid syndrome, endocarditis
(false negative treponemal test less likely but still repeat it)
if there is disparity between treponemal and non-treponemal test, which one should you repeat?
treponemal as is more specific
maximum PUQE score
15
(13 or more is ‘severe’)
Does Hbe antibody +ve mean they are high or low activity and infectivity
low infectivity
normal pO2 on ABG
11 - 13
normal pCO2 on ABG
4.5 - 6
normal bicarb on ABG
22 - 26
