Utility of the Platelet Function Analyzer in Patients with Suspected Platelet Function Disorders: Diagnostic Accuracy Study

Abstract

Introduction The platelet function analyzer (PFA) is widely used as a screening tool for bleeding disorders in various settings. The diagnostic performance regarding platelet function disorders (PFDs), which are among the most common inherited bleeding disorders, is however still elusive. We aimed to assess the diagnostic value of PFA for PFD in clinical practice. Methods Comprehensive clinical and laboratory data of all consecutive patients referred to a specialized outpatient between January 2012 and March 2017 with a suspected bleeding disorder were prospectively recorded. The diagnostic work-up was performed according to a prespecified protocol following current guidelines and platelet function was tested using light transmission aggregometry as well as flow cytometry. Results Five hundred and fifty-five patients were included (median age 43.7 years; interquartile range [IQR] 29.3, 61.7; 66.9% female). Possible PFD was diagnosed in 64 patients (11.5%) and confirmed PFD in 54 patients (9.7%). In patients with confirmed PFD, median closure times were 107 seconds (ADP or adenosine diphosphate; IQR 89, 130) and 169 seconds (EPI; IQR 121, 211). In patients without bleeding disorders, PFA closure times were 96 seconds (ADP; IQR 83, 109) and 137 seconds (EPI; IQR 116, 158). The sensitivity was 19.5% in case of PFA ADP (95%CI 12.6, 30.0; specificity 86.4%; 95% CI 82.4, 89.8), and 44.3% in case of PFA EPI (95% CI 34.9, 53.9; specificity 75.6%; 95% CI 70.8, 79.9). Conclusion The diagnostic performance of PFA for PFD was moderate to poor. Our results do not support the utilization of PFA for screening of PFD in clinical practice.

Bleeding Disorder of Unknown Cause: A Diagnosis of Exclusion

“…43 PFA-100 is not recommended as a screening test for PFD patients, 46 due to its low prevalence of prolonged closure times in comparison to healthy controls. 49,[61][62][63][64][65] In line, in the VIBB, 25% of all PFD patients did not show prolonged closure times with either PFA-100 with epinephrine or with ADP. 66 In our center, we perform LTA, flow cytometric mepacrine fluorescence, and glycoprotein expression analysis (►Fig.…”

Primary hemostasis in fetal growth restricted neonates studied via PFA-100 in cord blood samples

“…A study showed that platelets of neonates of preeclamptic mothers had a markedly higher responsiveness to agonists in vitro by flow cytometry; however, resting platelets of FGR neonates seemed to be in a slightly lower state of activation (47). Although the use of PFA as a screening tool for inherited platelet function disorders among adults has been questioned (48), prolongation of COL/EPI CT in the present study supports the impaired platelet function of FGR neonates reported from previous studies (13, 14, 47). It is of great importance that platelet hyporesponsiveness seems to apply for the whole group of FGR neonates irrespective of the cause.…”

ISTH bleeding assessment tool and platelet function analyzer in children with mild inherited platelet function disorders

“…9,12 Recent studies reported low sensitivity of the PFA in several mild platelet disorders. [11][12][13][14][15][16] Studies in pediatric populations show a similar heterogeneity. [17][18][19][20] The value of the studies investigating PFA to diagnose platelet function disorders in pediatric patients is limited, because most studies do not differentiate between specific IPFD diagnoses.…”

“…37,38 Similarly, in the other IPFD subgroup, we also measured median CTs that were not significantly longer than CTs of 'No diagnosis' patients. Kaufmann et al 16 included cases of α-SPD and reported only marginally prolonged CTs in all platelet function disorders. Our findings agree with most recent studies 16,20,37,38 reporting low sensitivity of the PFA to mild platelet function disorders.…”