Screening for Chronic Kidney Disease (CKD) in a high risk population using a Point of Care Instrument for creatinine measurement: A community based study (The Bellville South Africa Study)
Date
2017-12
Authors
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Journal ISSN
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Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT : Chronic kidney disease (CKD) is described as abnormal kidney function in which one third is
lost over a period of 3 months and is a global epidemic with a particularly concentrated
incidence within developing countries, such as Sub-Sahara Africa (SSA). Health facilities in
SSA are limited due to lack of funding and a dearth in disease and medical knowledge. This
coupled with the high incidence of both communicable and non-communicable diseases
makes for an ideal environment for the implementation of Point-of-Care Testing (POCT),
defined as an analytical test that is performed near the patient, delivering results in real time
without the need for a conventional laboratory. CKD POCT involves the measurement of
creatinine in capillary whole blood samples in order to determine the estimated glomerular
filtration rate (eGFR) of patients in order to stage their CKD status from stage 1-6.
This study aimed to bridge the gap in knowledge with regard to cut-offs of creatinine levels
and eGFR values when screening a mixed ancestry populations. Currently there is only
documented and standardized cut-offs for Caucasian and African American populations. This
study looked at the African mixed ancestry population and acts as a starting point for
standardizing POCT cut-offs for other international mixed ancestry populations.
103 participants were recruited from the Bellville South community, Cape Town, South Africa. The
study was a comparative study that was designed to evaluate the Nova Statsensor® point of care
instrument for the measurement of creatinine for the detection of CKD in adult mixed ancestry
subjects from the Bellville South Community in South Africa. Secondary objectives included (1)
the prevalence of CKD based on the results of the instrument, and (2) the correlation between the
Nova Statsensor®, and the central laboratory creatinine values (IDMS traceable). Ancillary
objectives of the study were to evaluate the technical quality of POC testing for creatinine in a
community setting, as well as the evaluation of the cost implications when introducing this form of
POCT into a primary care setting.
The study found that the Nova Statsensor® in this study had a sensitivity of 66.7% and a
specificity of 100%, displaying excellent diagnostic accuracy. It was found that the device
displayed negative proportional bias which may lead to future CKD patients being
misdiagnosed as healthy within screening programmes. The prevalence was found to be 2.9%
within this mixed ancestry population.
The device was user friendly and requires a small sample volume, however it is costly to
implement.
The laboratory evaluation study found that the Nova Statsensor® creatinine meter produced a
direct creatinine concentration comparison that was less than expected, possibly due to creatinine
levels depending on several factors which include muscle mass, obesity, gender, and age and
having a wide reference interval. Thus highlighting the importance of the use of the equations to
calculate eGFR in CKD screening in order to obtain the CKD staging results which displayed better
correlation to the reference method, compared to creatinine measurement alone. The device was
comparable to the reference method when performance was measured based on CKD staging
through the calculation of the MDRD equation.
AFRIKAANSE OPSOMMING : Geen Afrikaanse opsomming geskikbaar nie
AFRIKAANSE OPSOMMING : Geen Afrikaanse opsomming geskikbaar nie
Description
Thesis (MMedSc)--Stellenbosch University, 2017
Keywords
Blood -- Diseases -- Diagnosis, UCTD, Chronic kidney disease (CKD), Point-of-care testing (POCT), Creatine levels