Portable lactate test is reliable and accurate

A portable, hand-held device can provide quick and accurate measurements of blood lactate levels, investigators report in the December 1^st of the Journal of Acquired Immune Deficiency Syndromes.

Antiretroviral treatment programmes in resource-limited settings often include d4T (stavudine, Zerit). Possible side-effects of d4T include increased lactate levels or lactic acidosis, a rare but potentially fatal condition.

Lactic acidosis can be difficult to diagnose. Its symptoms can resemble those of other conditions, and measuring lactate levels is not feasible in many resource-limited settings because of a lack of laboratory facilities and the cost of tests.

Over two-thirds of patients receiving antiretroviral therapy at the Infectious Diseases Institute in Kampala, Uganda, take a d4T-containing regimen. Facilities to measure lactate levels are available, but the cost of such tests is expensive (US$7) and the time to report results can be lengthy.

Investigators at the clinic therefore compared the performance of a hand-held portable device and traditional laboratory methods to test lactate levels.

The hand-held device used at the unit was the Accutrend Lactate portable lactate analyser manufactured by Roche Diagnostics. The device is used in conjunction with disposable strips. The cost of the device is $235 and the strips costs between $1.24 and $1.60. Lactate levels can be measured by the device within one minute.

Between June and August 2007, blood samples were drawn from 55 patients. A drop of blood from these samples was used to measure lactate levels using the portable device, the rest of the sample being sent to the laboratory for lactate measurement using traditional methods.

The mean lactate level for the hand-held device was 3.12 (range, 1.01-6.0), with the mean value for the laboratory measurements being 3.06 (range, 0.9-7.4). This difference was not statistically significant (p = 0.47) and the results of the two testing methods were highly correlated.

The investigators write that there was “excellent agreement between the point-of-care machine and the reference method”.

A number of advantages of the portable testing device are outlined by the investigators including:

• The elimination of the need for centrifugation, storage and transport of samples.
• No need for specialised laboratory equipment or trained staff.
• Results available within 60 seconds, “thereby improving the clinicians’ ability to manage this life-threatening condition”.

“In conclusion”, write the investigators, “we found that the portable hand-held analyzer is accurate, reliable, and can be used in ART programs in our setting where the majority of patients are taking stavudine-containing regimens”.