Applicability and precautions of use of liver injury biomarker FibroTest. A reappraisal at 7 years of age

BMC Gastroenterology

Table 4 Review of high risk FibroTest using charts in the reference center (P4)

Components of FibroTest with high risk profile	Number of Tests Identified	Reviewed (Traceability)¹	Correctly classified		Indeterminate	Incorrectly classified
			True Positive	True Negative		False positive	False negative
Haptoglobin
< = 0.08 g/L	324	214 (66%)	58 (27%)	0 (0%)	42 (20%)	114 (53%)²	0 (0%)
> = 3.20 g/L	0	0 (100%)	0	0	0	0	0
Apolipoprotein A1
< = 0.56 g/L	25	17 (68%)	15 (88%)	0	0 (0%)	2 (12%)³	0 (0%)
> = 2.50 g/L	57	38 (67%)	1 (3%)	30 (79%)	4 (10%)	0 (0%)	3 (8%)⁴
Alpha-2 macroglobulin
< = 0.80 g/L	54	32 (59%)	3 (10%)	24 (75%)	0 (0%)	0 (0%)	5 (15%)⁵
> = 5.90 g/L	24	24 (100%)	22 (92%)	0	2 (8%)	0 (0%)	0 (0%)
GGT IU/L > = 1140 IU/L	8	6 (75%)	1 (16%)	1 (16%)	2 (33%)	2 (33%)⁶	0 (0%)
Total Bilirubin, μmol/L > = 50	0	0 (100%)	0	0	0	0	0
Total	491	331 (67%)	100 (30%)	55 (17%)	50 (14%)	118 (36%)	8 (2%)

¹ Inpatients with detailed charts reviewed by 3 experts. (Supplement file S3)
When biopsy was performed (5 years apart) it was taken as a reference; when no biopsy had been performed but an LSM was interpretable it was taken as a reference (advanced fibrosis if greater than 7.1 kPa); when oesophageal varices or ascites were present it was taken as advanced fibrosis; for low hapto, if no reference and a cause of hemolysis was identified FT > = 0.48 was considered false positive. When no reference was present without a clear cause of component error (such as hemolysis for hapto or severe undernutrition for A2M and apoA1, the case was stated to be indeterminate.
² Low haptoglobin, already known causes: hemolysis with patent cause: cardiac prosthesis (n = 25), drepanocytosis (n = 13), ribavirin (n = 8), thalassemia (n = 2), autoimmune (n = 2); anahaptoglobinemia (n = 1). Two new possible causes were HIV co-infection (n = 14) and splenectomy (n = 4)
³ Low ApoA1 already known cause: severe undernutrition (n = 2 total serum proteins < = 50 g/L)
⁴ High ApoA1 suspected analytical error or an unknown transient factor as in 2 cases, 2 repeated ApoA1 assays were in normal range
⁵ Low A2M already known causes: large ascites (n = 3), severe undernutrition (n = 1 total serum proteins < = 50 g/L); a new possible cause was macrophage activation syndrome (n = 1)
⁶ High GGT already known cause: chronic pancreatitis (n = 2)

ISSN: 1471-230X