This calculator estimates the 12-month risks of progression to AIDS and
death, based on the patientís age and one of the following markers:
CD4 percent, CD4 count, total lymphocyte count, or viral load. The estimates
should only be used for guidance on when to initiate ART, and not as a hard
and fast rule. Such decisions should take account of other information, including
the childís clinical status, the familyís preparedness to start therapy,
adherence, etc. See
for further information.
| 1. Choose data to enter:
Other important points to bear in mind when
interpreting these estimates are:
• Predictions are unreliable after about age
12 years because of small numbers of older children. Predictions may
also be inaccurate in very young infants as markers are highly variable
at this age.
The generalisability of these estimates
is an issue since they are based on data going back to the mid-1980s
from a diverse population. In particular, their accuracy has not been
verified in resource-limited settings.
The different markers may give very different
estimates of risk for an individual child. Preliminary analyses
indicate that the strongest individual predictor is CD4 count,
followed by CD4 percent, followed by total lymphocyte count, followed by
viral load. Alternatively, it may be prudent to base decisions on the
highest of the estimates.
All the markers are subject to high within-patient
variability and measurement error. It is strongly recommended to repeat
a test to confirm a single abnormal value.