- ART efficacy is monitored with VL and CD4+ count – discussed in Module 8 and Module 9.
- The key efficacy endpoint in ART is sustained virological suppression with a VL < 50 copies/mL.
- CD4+ count monitoring can be stopped when CD4+ count > 200 cells/μL and the VL is suppressed.
- Creatinine monitoring is advised in patients on TDF, and full blood count (FBC) in patients on AZT.
- In most patients taking PIs, only one lipid measurement is advised (at 3 months).
In patients on TDF who are admitted to hospital, it is important to assess creatinine even if it does not fall within these monitoring guidelines. This is because intercurrent illnesses with dehydration or sepsis may be associated with deterioration in renal function, in which TDF may act as a co-factor.
Table 18 lists the laboratory investigations and their frequency advised for monitoring of ART safety.
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|TABLE 18: Standard laboratory monitoring of patients after commencement of antiretroviral therapy.|
|VL||Yes||At 3 months, 6 months and then 6-monthly||If VL undetectable for > 12 months, then can reduce to 12-monthly.|
|CD4+ count||Yes||6-monthly; and at virological/clinical failure||Can be stopped if CD4+ count > 200 cells/μL and virologically suppressed.|
|FBC and differential count||Yes||Monthly for the first 3 months, then at 6 months for patients on AZT-containing regimens||
This test is only required for patients commencing AZT-containing regimens.
|ALT||Yes||At initiation||If baseline ALT is normal, then routine monitoring of ALT is not required.|
|CrCl||Yes||At 3 months, 6 months and then 6-monthly||Also at 1 month and 2 months in high-risk patients. If there are symptoms of tubular wasting (e.g. muscle weakness), then check potassium and phosphate levels.|
|TC and TG||Not routinely||After 3 months on a PI-containing regimen||If normal at 3 months, then reassess only if other cardiovascular risk factors are present.|
ALT, alanine transaminase; AZT, zidovudine; CrCl, creatinine clearance rate; FBC, full blood count; NVP, nevirapine; TC, total cholesterol; TG, triglycerides; VL, viral load.
Common pitfall: Monitoring of VL is not performed at least annually. This results in delayed detection of ART failure and intervention, with resultant clinical deterioration and increased risk of transmission.