Brief Report: Hair Testing to Detect Long-term Methamphetamine Use in People Living With and Without HIV.

BACKGROUND

The United States (US) faces an unprecedented surge in methamphetamine (MA) use, with severe implications for people living with HIV or at risk of HIV acquisition. Current detection methods, including self-report and urine testing, have significant limitations. Hair testing represents a promising alternative for quantifying longer-term substance exposure but requires validation in clinical research settings.

SETTING

US-based cohort of men with and at-risk of HIV in Los Angeles (mSTUDY).

METHODS

We conducted a cross-sectional validation study using data from mSTUDY. We analyzed hair samples from 2 groups with negative urine MA tests: individuals reporting daily/weekly MA use (n = 22) and controls reporting no MA use (n = 22). Hair was analyzed using liquid chromatography-tandem mass spectrometry, with MA positivity defined as concentrations >200 pg/mg per Society of Hair Testing guidelines.

RESULTS

Hair analysis detected MA use in 17/22 (77%) participants reporting regular use despite negative urine tests. Among controls reporting no MA use, 3 of 22 (14%) had positive hair samples. The positive likelihood ratio for detecting MA use not identified by urine testing was 6.0 (95% CI: 2.1 to 17.3), with sensitivity of 77.3% (95% CI: 56.6% to 89.9%) and specificity of 86.4% (95% CI: 66.7% to 95.3%). Among people living with HIV, those reporting MA use had lower rates of virologic suppression compared with those without reported use (45% vs 82%, P = 0.05).

CONCLUSIONS

Hair testing successfully identified past-month MA use not detected by urine testing, with strong diagnostic performance. This validated biomarker provides objective measurement of longer-term MA use patterns, offering an important complement to current detection methods in substance use and HIV research.