AACC Updates Guidelines for Use of Reproductive POC Testing
The new guidelines address issues with false negatives and positives from POC testing for fertility and reproductive health.
The influential American Association for Clinical Chemistry (AACC) has been a leading source of guidance on safe, proper, and effective use of point-of-care (POC) laboratory testing. In 2007, the AACC published guidelines on evidence-based practice for POC testing.1 Now the organization is revising those original guidelines and recommendations. On Aug. 29, the AACC updated its guidelines pertaining to POC testing for fertility and reproductive health. Here is a quick briefing on the revised guidelines.2
POC Reproductive Testing
Performing tests at the point of care rather than an offsite laboratory offers distinct advantages, including faster test results reporting and elimination of specimen transport and other pre-testing processes. POC tests can be administered by physicians and others without primary training in clinical laboratory sciences, sometimes even the patients themselves, using kits purchased over the counter without a prescription. This potent combination of speed, convenience, and lower costs has driven significant growth in POC testing in recent years.
But, as the AACC notes, there is a tradeoff. Stated simply, there is a higher risk of inaccurate results when laboratory tests are performed at the point of care. Although test manufacturers provide instructions with their products, those instructions are not always followed. The guidelines cite some of the things that can go wrong, including:
- Improper storage of reagents;
- Incorrect sample collection;
- Not using enough of the sample; and
- Over- or under-timing test development.
The resulting false negative or positive results from POC tests may lead to unnecessary follow-up testing and medical treatment or, even worse, failure to get such testing and treatment when it is medically necessary.
The AACC Guidelines
With these risks in mind, the AACC (which was then called the National Academy of Clinical Biochemistry) was among the first to publish guidance setting out laboratory best practices for clinicians and providers to follow when using POC tests for patient care. Those best practices are now 15 years old and in need of updating to account for new technologies and studies of POC testing practices. However, the 2007 guidelines are nearly 200 pages long. So, rather than do everything at once, the AACC is revising the guidelines one section at a time, on the basis of priority.
The most recent guidance document revisits the original recommendations on POC testing for fertility and reproduction. Here is an overview of the key recommendations.
POC Ovulation Testing
According to the guidelines, ultrasonography, luteinizing hormone (LH), estradiol, and progesterone testing are considered the gold standard for clinical monitoring of ovulation and ovarian function of women seeking to conceive. However, POC tests like basal body temperature (BBT) measurement, salivary and vaginal mucus ferning, and urinary LH/estrone-3-glucuronide (E3G) testing are simpler and more convenient alternatives for predicting the start and duration of a woman’s ovulation.
AACC Recommendations: Urine LH tests “are accurate and reliable predictors of ovulation” that can help “healthy fertile women” improve their chances of conception. LH tests may also be useful in timing certain assisted reproduction procedures. However, the guidelines caution that “further study is needed to determine the efficacy” of BBT and saliva at-home ovulation prediction kits.
POC hCG Pregnancy Testing
The rapid rise in beta-human chorionic gonadotropin (hCG) protein serum levels after conception is an early biomarker of pregnancy. Assays detecting elevated hCG can be performed at a laboratory or the point of care.
AACC Recommendations: The guidelines recommend considering the use of POC as an alternative to laboratory hCG testing “in clinical situations where rapid diagnosis of pregnancy is needed for treatment decisions and laboratory analysis cannot meet the required turnaround time.” Examples: A positive urine or whole blood POC hCG combined with ultrasound might be appropriate in acute settings for patients with unstable vital signs and symptoms of ruptured ectopic pregnancy requiring immediate intervention.
POC Premature Rupture of Membranes Testing
Premature rupture of membranes (PROM) that can threaten a pregnancy is detected via observation of pooled amniotic fluid, pH testing of vaginal and amniotic fluid, and microscopic analysis revealing ferning patterns in dried vaginal fluid. However, there are also a number of commercial POC PROM detection kits available.
AACC Recommendations: Most cases of PROM can be diagnosed via “physical examination, clinical presentation, and patient history,” according to the guidelines. PROM testing using commercial kits alone is not recommended unless there are clinical signs that a patient’s water has broken. In addition, “results from these tests must be interpreted in the context of a patient’s clinical presentation to prevent patient harm.” There have also been “reports of misuse resulting in death and health complications for fetus and/or mother,” the guidelines caution.
POC Fetal Scalp Lactate/Cord Blood Gas Testing
POC tests that measure fetal blood scalp (FBS) lactate levels can be used to predict and prevent a serious condition called fetal acidosis.
AACC Recommendations: Current studies suggest that FBS testing “has minimal utility” in preventing metabolic acidosis, according to the guidelines. Nor is there adequate evidence to conclude that FBS testing reduces the rate of caesarian births. The AACC also recommends use of precision analysis and method comparison between POC testing devices vs laboratory-based blood gas analyzers for validating fetal lactate devices.
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