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Point-of-care tests in behavioral health

April 1, 2006
by William M. Glazer, MD
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Glucose monitoring and a new lithium test can provide instant results to patients and clinicians

New technologies and patient care models are driving laboratory testing to the patient's side—at the point of care (POC). POC testing is diagnostic testing or therapeutic monitoring carried out at or near the site of the patient. By using whole blood or other bodily specimens, POC testing eliminates the time lag associated with laboratory testing and leads to rapid results for quicker therapeutic action and improved patient outcomes and satisfaction.

While such in-office testing is relatively new to behavioral healthcare, it is not a new approach in general medicine. More than 90,000 medical offices perform POC testing in the United States. Familiar POC tests include those that determine blood glucose, pregnancy, strep throat, substances of abuse, and prothrombin time. In-office testing in behavioral healthcare settings is emerging as a method to monitor effects of medications used to treat conditions such as schizophrenia and bipolar disorder.

POC Testing and Antipsychotics

Antipsychotics treat signs and symptoms such as hallucinations, delusions, disordered thinking, mania, and depression in people suffering from schizophrenia or bipolar disorder. Both of these conditions are chronic, often beginning in young adulthood. Schizophrenia affects 1% of the general population, and bipolar disorder affects 3%. Because of their chronicity, these two conditions account for a sizeable proportion of overall behavioral healthcare costs.

Clinical studies of the atypical antipsychotics have observed weight gain, abnormal lipid levels, and elevated blood sugar in pa-tients—signs of metabolic syndrome, which leads to heart disease and serious medical consequences. These side effects are serious because patients with schizophrenia and/or bipolar disorder, independent of medications, are at greater risk for cardiovascular disease.1,2

As a result of the concern about metabolic syndrome and cardiovascular disease, behavioral healthcare providers now are focused on screening for these conditions.3 The clinical indicators of interest are:

  • high blood pressure (i.e., ≥130/85 mmHg)

  • waist circumference >40" in males and >35" in females

  • fasting blood sugar >110 mg/dl

  • fasting HDL cholesterol <40 mg/dl in males and <50 mg/dl in females

  • fasting triglycerides ≥150 mg/dl

A recent study of patients with schizophrenia or bipolar disorder treated with atypicals found a 29.2% prevalence of metabolic syndrome.4 This study found that when elevated abdominal obesity and fasting blood glucose levels were combined, all patients with metabolic syndrome were accurately identified. The authors concluded that these two measures constituted the most cost-effective way to screen for metabolic syndrome in this patient population.

The availability of POC testing methods for blood glucose levels creates new opportunities for behavioral healthcare providers to monitor drug therapy and screen for complications in patients with diabetes. Instant glucose meters and strips are advertised widely on television and in the print media, and they are now widely used among prediabetic and diabetic patients. Reimbursement is possible since many of these tests are “CLIA-waived” by the FDA. A CLIA-waived (Clinical Laboratory Improvement Amendments) test has been tested in three clinical studies using untrained people who, after reading the instructions, perform the test, and the test performs as described without adverse effects. Once a device is CLIA-waived, it can be used in office environments instead of laboratory environments. Behavioral healthcare providers have reason to perform this measure because, based on my and many others’ observations, patients with schizophrenia or bipolar disorder often avoid primary care contacts.

POC Testing and Lithium

Since the 1970s, lithium has been a mainstay of bipolar disorder treatment and an effective augmentation strategy for treatment-resistant unipolar depression and schizophrenia. Despite lithium's efficacy, many psychiatrists find regular monitoring of lithium blood levels to be burdensome for their patients and for themselves (table 1).

Lithium is a benchmark drug, but the amount for effectiveness is slightly less than toxic levels, so clinicians must monitor levels to ensure maintenance of therapeutic ranges. Lithium is underused in the United States, yet it has the most extensive evidence base for long-term efficacy for bipolar disorder compared with any other drug.5 Lithium is highly rated in many treatment guidelines including those from the Veterans Administration and American Psychiatric Association, and in the Expert Consensus Guidelines.6 Such underuse is particularly notable given the evidence for lithium's potency for suicide prevention.7–9 Only about 400,000 patients are on lithium in the United States out of a total potential population of more than four million.10