diff --git a/README.md b/README.md
index 566d146..837b723 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,7 @@ Dependencies:
 - R version 4.1.1
 - PLINK version 2.00a2.3
 - CNA version 0.1.6
+- Rmpfr version 0.8-7
 
 # Tutorial
 We illustrate how to use `GeNA` in a tutorial [here](https://github.com/immunogenomics/GeNA/blob/main/tutorial/Example_csaQTL_GWAS.ipynb). First, we demonstrate how to construct the single-cell data object format `GeNA` expects, then we summarize the arguments input to and files output from a call to `GeNA`. Finally, we illustrate basic characterization of example loci.
diff --git a/joint_test.R b/joint_test.R
index 9fe4019..5353597 100644
--- a/joint_test.R
+++ b/joint_test.R
@@ -1,4 +1,7 @@
-library(argparse)
+suppressPackageStartupMessages({
+	library(argparse)
+	library(Rmpfr)
+})
 set.seed(0)
 
 # Parse Arguments
@@ -7,11 +10,10 @@ parser$add_argument("--chisq_per_nampc_file",type="character")
 parser$add_argument("--ks_file",type="character")
 parser$add_argument("--outfile",type="character")
 args <- parser$parse_args()
-#cat("\n\n****")
-#print(args)
-#cat("****\n\n")
 
-all_res = read.table(args$chisq_per_nampc_file, header=FALSE)
+mht_correct <-function(raw_p, len_ks, prec_bits = 100){asNumeric(mpfr(1, prec_bits)-(mpfr(1, prec_bits)-mpfr(raw_p, prec_bits))**len_ks)}
+
+all_res = read.table(args$chisq_per_nampc_file, header=FALSE) # T values
 all_res = all_res**2 # T-squared
 ks = read.table(args$ks_file, header=FALSE)[,1]
 
@@ -19,7 +21,13 @@ for(k in ks){
     all_res[paste0("k",k,"_P")] = apply(as.matrix(rowSums(all_res[,c(1:k), drop=FALSE]), ncol=1), 1, pchisq, df = k, lower = F)
 }
 all_res['P'] = apply(as.matrix(all_res[,paste0("k",ks,"_P"), drop=FALSE], ncol=length(ks)), 1, min)
+small_vals = which(all_res[,'P']<1e-15) # If p<2.2e-16, need small-values handling
+small_vals_p = all_res[small_vals,'P']
 all_res['P'] = 1-(1-all_res['P'])**length(ks)
 all_res['k']= apply(as.matrix(all_res[,paste0("k",ks,"_P"), drop=FALSE], ncol=length(ks)), 1, which.min)
 all_res['k'] = ks[all_res$k]
+
+# Small-values handling with precision
+all_res[small_vals,'P'] = apply(as.matrix(small_vals_p), 1, mht_correct, length(ks))
+
 write.table(all_res[,c("P", "k")], args$outfile, quote=FALSE, row.names=FALSE, sep = "\t")
\ No newline at end of file