Vertesi reported a Risk Assessment Stratification Protocol (RASP) for determining the severity of a possible exposure to HIV. This can help to determine if a patient should receive post-exposure prophylaxis. The author is from Royal Columbian Hospital in British Columbia.
Parameters:
(1) source
(2) inoculum type
(3) method of transmission
(4) estimated volume of onoculum
Parameter
Finding
Points
source
HIV positive with acute AIDs illness
1
HIV positive, asymptomatic
10
unknown HIV status, high risk
100
unknown HIV status, low risk
1000
inoculum
fresh blood
1
high-risk body fluid (semen, etc)
10
dried old blood
100
low risk secretion (tears, saliva, urine)
1000
method of transmission
intravenous
1
deep intramuscular
10
deep transcutaneous with visible bleeding at site
100
superficial transcutaneous with no visible bleeding
200
mucosal contact only
500
intact skin
1000
volume of inoculum
massive (blood transfusion)
100
> 1 mL
10
large-bore hollow needle larger than 22 gauge
5
small-bore hollow needle 22 gauge or less
3
suture needle, trace surface only
1
where:
• A high-risk source includes suspected HIV, injection drug user, high local prevalence of HIV
basic risk =
= 1 / ((points for source) * (points for inoculum) * (points for method of transmission))
total risk =
= (volume of inoculum) * (basic risk)
Interpretation:
• minimum basic risk: 1 in 10^9
• maximum basic risk: 1 in 1
• minimum total risk: 1 in 10^9
• maximum total risk: 100
Total Risk
Prophylaxis
greater than 1 in 1000
indicated
1 in a 1000 to 1 in 10,000
recommended
1 in 10,001 to 1 in 100,000
optional but not recommended
less than 1 in 100,000
no indicated
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