URINE LAM TEST FOR HIV POSITIVE ADULTS

ADOPTION OF URINE LAM TEST FOR HIV POSITIVE ADULTS WITH SIGNS AND SYMPTOMS OF TB, CD4 COUNT LESS THAN OR EQUAL TO 100 CELLS/ML, OR VERY ILL HIV POSITIVE PATIENTS REGARDLESS OF THEIR CD4 COUNT

Tuberculosis (TB) and HIV/AIDS remain major public health problems in Uganda, y=the HIV prevalence
is estimated at 7.3% and 42% of the TB patients are co-infected with HIV. The Ministry of Health places
a lot of emphasis on delivering integrated TB/HIV services to effectively control the dual epidemics.

Background

Tests based on the detection of mycobacterial lipoarabinomannan (LAM) antigen in urine have emerged as potential point-of-care tests for tuberculosis (TB). LAM antigen is a lipopolysaccharide present in mycobacterial cell walls, which is released from metabolically active or degenerating bacterial cells and appears to be present only in people with active TB disease. Urine-based testing would have advantages over sputum-based testing because urine is easy to collect and store, and lacks the infection control risks associated with sputum collection.

WHY LAM AND WHEN TO USE IT

The WHO recommends that urine LAM may be used to assist in the diagnosis of TB in HIV positive adult
in-patient with signs and symptoms of TB (pulmonary or extra pulmonary) who have a CD4 cell count less
than or equal to 100cells/microliters, who HIV positive patients who are seriously ill regardless of
CD4 count or unknown CD4 count because HIV positive patients with TB may be missed since sputum bacillary
load is typically low in these patients, they may not be able to provide sufficient and high quality specimens
and majority of these patients have extra-pulmonary TB without pulmonary TB, these patients also register high
rates of mortality. The LAM urine test detects a glycolipid molecule called lipoarabinoamannan (LAM), a protein
present in mycobacterial cells, which is released from metabolically active or degenerating bacterial cells and
appears to be in only people with active TB disease.

The Ministry of Health, National TB and Leprosy Program, has adopted the use of the LAM urine test as an add
on test (i.e. do Lam after performing available laboratory tests and results are negative), integrated it in
the National TB Diagnostic Algorithim and also highlighted it in the National TB and Leprosy Program Strategic
Plan as one of the strategies to find the missed TB cases especially among HIV positive patients with signs
and symptoms with a negative microscopy or genexpert result or are unable to produce sputum, have a CD4 less
than or equal to 100copies/microliter, or the HIV positive patients who are very ill regardless of CD4 count or unknown CD4 count, because;

  1. It is recommended by WHO
  2. Studies conducted in 10 hospitals in sub Saharan Africa demonstrated that urine LAM, used in conjunction with routine testing, reduced the rate of TB related death among HIV patients because probably the test led to a greater proportion of the patients getting treatment early and the test effectively identified TB among the very sick HIV patients.
  3. A pilot in all the National and Regional Referral Hospitals in Uganda indicated a 7% increase in the number of TB cases detected by these facilities and there is no need for infrastructure or biosafety requirements.

Patients with a positive urine LAM result should be classified as clinically diagnosed TB – EPTB and it should be properly recorded in the facility TB registers.

 

For more about Tuberculosis, click here.