Half of the world's population lacks access to basic medical tests essential for diagnosing a disease. Even pregnant women find it difficult to obtain basic tests, such as hepatitis B and syphilis, said an analysis on Thursday.    

According to the study led by The Lancet Commission on Diagnostics, nearly half or 47 percent of the global population have limited or no access to tests for diabetes, hypertension, HIV and tuberculosis.  

Without accurate, high-quality and affordable diagnostics, many people will be overtreated, undertreated or not treated at all, or exposed to unnecessary and potentially harmful treatment, warned the study.  

"In much of the world, patients are treated for diseases in the absence of access to key diagnostic tests and services. This is the equivalent of practicing medicine blind," said Doctor Kenneth Fleming, commission chair at the University of Oxford.  

"Not only is this potentially harmful to patients, but it is also a significant waste of scarce medical resources. For the first time, our analysis shows the shocking scale of the challenges we are facing," Fleming added.

For diagnosing a patient, a doctor requires a collection of crucial tests of blood, tissue and urine samples tested in a laboratory. They also need diagnostic imaging such as x-rays, ultrasound, MRI, CT scan, or nuclear medicine.

Syphilis, urine dipsticks, hemoglobin, blood glucose and ultrasounds, which represent basic diagnostic tests, should be available within two hours after a patient is admitted to a hospital.

According to public health experts, narrowing the diagnostic gap for just six conditions, diabetes, hypertension, HIV, tuberculosis, hepatitis B and syphilis for pregnant women, from 62 percent to 10 percent would reduce the number of premature deaths in low-income and middle-income countries by 1.1 million annually.

The analysis is based on World Health Organization data. According to the study, the diagnostic gap is greatest in primary care, where only about 19 percent of populations in low- and lower-middle-income countries have access to the simplest diagnostic tests.

"There are three essential things for health security: diagnostics security, vaccine security and therapeutic security. Strong health systems and strong public health system require all three," said Doctor John Nkengasong, co-author of the commission.

Researchers have recommended urgent investment and training to improve access to testing in primary care, especially point-of-care testing. The commission estimated a global shortfall of up to one million diagnostic staff requiring investment into training and education to fill the gap.

The commission also recommends that countries urgently develop national diagnostics strategies to provide populations with access to a set of essential diagnostics appropriate for the local health care needs.

(Cover: A nurse tends to a tuberculosis patient at the Mae Tao clinic in the northwest Thai town of Mae Sot, May 23, 2007. /Reuters)