diff --git a/app/Controllers/AbdmGateway.php b/app/Controllers/AbdmGateway.php
index 41b1ea2..ac6e7ce 100644
--- a/app/Controllers/AbdmGateway.php
+++ b/app/Controllers/AbdmGateway.php
@@ -966,6 +966,7 @@ class AbdmGateway extends BaseController
         $organization = $hospitalProfile['name'] !== ''
             ? ['name' => $hospitalProfile['name'], 'hfr_id' => $hospitalProfile['hfr_id']]
             : null;
+        $practitioner = $this->resolveLabPractitionerForFhir($labReqId, $labReq);
 
         $encounter = [
             'id'           => 'LAB-' . $labReqId,
@@ -988,7 +989,7 @@ class AbdmGateway extends BaseController
             ]);
         }
 
-        $bundle     = $fhir->buildLabReportBundle($patient, $diagnosticReport, $observations, null, $organization, $encounter, $pdfAttachment);
+        $bundle     = $fhir->buildLabReportBundle($patient, $diagnosticReport, $observations, $practitioner, $organization, $encounter, $pdfAttachment);
         $bundleJson = (string) json_encode($bundle, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
 
         // ── Store health_record ───────────────────────────────────────────────
@@ -1138,6 +1139,7 @@ class AbdmGateway extends BaseController
         $organization = $hospitalProfile['name'] !== ''
             ? ['name' => $hospitalProfile['name'], 'hfr_id' => $hospitalProfile['hfr_id']]
             : null;
+        $practitioner = $this->resolveLabPractitionerForFhir($labReqId, $labReq);
 
         $encounter = [
             'id'           => 'LAB-' . $labReqId,
@@ -1169,7 +1171,7 @@ class AbdmGateway extends BaseController
             ]);
         }
 
-        $bundle = $fhir->buildLabReportBundle($patient, $diagnosticReport, $observations, null, $organization, $encounter, $pdfAttachment);
+        $bundle = $fhir->buildLabReportBundle($patient, $diagnosticReport, $observations, $practitioner, $organization, $encounter, $pdfAttachment);
 
         return $this->response->setJSON([
             'status' => 'ok',
@@ -2472,6 +2474,167 @@ class AbdmGateway extends BaseController
         return ['name' => $name, 'hfr_id' => $hfrId];
     }
 
+    /**
+     * Resolve practitioner details for lab/radiology DiagnosticReportRecord.
+     *
+     * Best-effort strategy:
+     * 1) read doctor id/name/registration from lab_request (when present)
+     * 2) enrich from doctor_master using doctor id
+     *
+     * @param int                     $labReqId
+     * @param object|array<string,mixed>|null $labReqRow
+     * @return array<string,string>|null
+     */
+    private function resolveLabPractitionerForFhir(int $labReqId, $labReqRow = null): ?array
+    {
+        if ($labReqId <= 0 || ! $this->db->tableExists('lab_request')) {
+            return null;
+        }
+
+        $doctorId = 0;
+        $doctorName = '';
+        $doctorRegNo = '';
+
+        $candidateIdCols = ['doctor_id', 'dr_id', 'doc_id', 'r_doc_id', 'consultant_id', 'reported_by_doctor_id'];
+        $candidateNameCols = ['doctor_name', 'dr_name', 'doc_name', 'r_doc_name', 'consultant_name', 'reported_by_name', 'reported_by'];
+        $candidateRegCols = ['doctor_reg_no', 'registration_no', 'reg_no', 'doctor_registration_no'];
+
+        // Try immediate row first (if caller passed a richer row object/array).
+        if (is_object($labReqRow)) {
+            foreach ($candidateIdCols as $c) {
+                if (isset($labReqRow->{$c}) && (int) $labReqRow->{$c} > 0) {
+                    $doctorId = (int) $labReqRow->{$c};
+                    break;
+                }
+            }
+            foreach ($candidateNameCols as $c) {
+                $v = isset($labReqRow->{$c}) ? trim((string) $labReqRow->{$c}) : '';
+                if ($v !== '') {
+                    $doctorName = $v;
+                    break;
+                }
+            }
+            foreach ($candidateRegCols as $c) {
+                $v = isset($labReqRow->{$c}) ? trim((string) $labReqRow->{$c}) : '';
+                if ($v !== '') {
+                    $doctorRegNo = $v;
+                    break;
+                }
+            }
+        } elseif (is_array($labReqRow)) {
+            foreach ($candidateIdCols as $c) {
+                if (isset($labReqRow[$c]) && (int) $labReqRow[$c] > 0) {
+                    $doctorId = (int) $labReqRow[$c];
+                    break;
+                }
+            }
+            foreach ($candidateNameCols as $c) {
+                $v = isset($labReqRow[$c]) ? trim((string) $labReqRow[$c]) : '';
+                if ($v !== '') {
+                    $doctorName = $v;
+                    break;
+                }
+            }
+            foreach ($candidateRegCols as $c) {
+                $v = isset($labReqRow[$c]) ? trim((string) $labReqRow[$c]) : '';
+                if ($v !== '') {
+                    $doctorRegNo = $v;
+                    break;
+                }
+            }
+        }
+
+        try {
+            $labFields = $this->db->getFieldNames('lab_request') ?? [];
+            $selectCols = ['id'];
+            foreach (array_merge($candidateIdCols, $candidateNameCols, $candidateRegCols) as $c) {
+                if (in_array($c, $labFields, true)) {
+                    $selectCols[] = $c;
+                }
+            }
+
+            if (count($selectCols) > 1) {
+                $labDbRow = $this->db->table('lab_request')
+                    ->select(implode(',', array_unique($selectCols)))
+                    ->where('id', $labReqId)
+                    ->get(1)
+                    ->getRowArray() ?? [];
+
+                if (! empty($labDbRow)) {
+                    if ($doctorId <= 0) {
+                        foreach ($candidateIdCols as $c) {
+                            if (isset($labDbRow[$c]) && (int) $labDbRow[$c] > 0) {
+                                $doctorId = (int) $labDbRow[$c];
+                                break;
+                            }
+                        }
+                    }
+                    if ($doctorName === '') {
+                        foreach ($candidateNameCols as $c) {
+                            $v = isset($labDbRow[$c]) ? trim((string) $labDbRow[$c]) : '';
+                            if ($v !== '') {
+                                $doctorName = $v;
+                                break;
+                            }
+                        }
+                    }
+                    if ($doctorRegNo === '') {
+                        foreach ($candidateRegCols as $c) {
+                            $v = isset($labDbRow[$c]) ? trim((string) $labDbRow[$c]) : '';
+                            if ($v !== '') {
+                                $doctorRegNo = $v;
+                                break;
+                            }
+                        }
+                    }
+                }
+            }
+        } catch (\Throwable $e) {
+            // fail-open; continue with what we already have
+        }
+
+        if ($doctorId > 0 && $this->db->tableExists('doctor_master')) {
+            try {
+                $dFields = $this->db->getFieldNames('doctor_master') ?? [];
+                $dSelect = ['id'];
+                foreach (['p_fname', 'p_lname', 'doctor_reg_no', 'registration_no', 'reg_no'] as $f) {
+                    if (in_array($f, $dFields, true)) {
+                        $dSelect[] = $f;
+                    }
+                }
+
+                $dRow = $this->db->table('doctor_master')
+                    ->select(implode(',', array_unique($dSelect)))
+                    ->where('id', $doctorId)
+                    ->get(1)
+                    ->getRowArray() ?? [];
+
+                if ($doctorName === '' && ! empty($dRow)) {
+                    $doctorName = trim(trim((string) ($dRow['p_fname'] ?? '')) . ' ' . trim((string) ($dRow['p_lname'] ?? '')));
+                }
+                if ($doctorRegNo === '' && ! empty($dRow)) {
+                    foreach (['doctor_reg_no', 'registration_no', 'reg_no'] as $f) {
+                        if (! empty($dRow[$f])) {
+                            $doctorRegNo = trim((string) $dRow[$f]);
+                            break;
+                        }
+                    }
+                }
+            } catch (\Throwable $e) {
+                // fail-open
+            }
+        }
+
+        if ($doctorName === '') {
+            return null;
+        }
+
+        return [
+            'name' => $doctorName,
+            'registration_number' => $doctorRegNo,
+        ];
+    }
+
     /**
      * Map numeric lab_type code to a human-readable title.
      */
diff --git a/app/Libraries/FhirR4Builder.php b/app/Libraries/FhirR4Builder.php
index 8b0f976..e42df43 100644
--- a/app/Libraries/FhirR4Builder.php
+++ b/app/Libraries/FhirR4Builder.php
@@ -132,7 +132,7 @@ class FhirR4Builder
                 'display' => 'Ambulatory',
             ],
             'subject' => ['reference' => $patientRef, 'display' => 'Patient'],
-            'period'  => ['start' => trim((string) ($encounter['period_start'] ?? '')) !== '' ? (string) $encounter['period_start'] : $issuedAt],
+            'period'  => ['start' => $this->normalizeIsoDateTime((string) ($encounter['period_start'] ?? ''), $issuedAt)],
         ];
         if ($practitionerRef !== '') {
             $encounterResource['participant'] = [['individual' => ['reference' => $practitionerRef]]];
@@ -657,7 +657,7 @@ class FhirR4Builder
 
         $patientRef  = 'urn:uuid:' . $patientUuid;
         $reportRef   = 'urn:uuid:' . $reportUuid;
-        $reportedAt  = trim((string) ($diagnosticReport['reported_at'] ?? '')) ?: $issuedAt;
+        $reportedAt  = $this->normalizeIsoDateTime((string) ($diagnosticReport['reported_at'] ?? ''), $issuedAt);
         $reportTitle = trim((string) ($diagnosticReport['title'] ?? 'Diagnostic Report'));
         $reportStatus = trim((string) ($diagnosticReport['status'] ?? 'final'));
         $isImaging   = (bool) ($diagnosticReport['is_imaging'] ?? false)
@@ -734,12 +734,15 @@ class FhirR4Builder
                 ],
                 'subject' => ['reference' => $patientRef, 'display' => 'Patient'],
             ];
-            $pStart = trim((string) ($encounter['period_start'] ?? ''));
-            if ($pStart !== '') {
-                $encounterRes['period'] = ['start' => $pStart];
-                $pEnd = trim((string) ($encounter['period_end'] ?? ''));
-                if ($pEnd !== '') {
-                    $encounterRes['period']['end'] = $pEnd;
+            $pStartRaw = trim((string) ($encounter['period_start'] ?? ''));
+            if ($pStartRaw !== '') {
+                $encounterRes['period'] = ['start' => $this->normalizeIsoDateTime($pStartRaw, $issuedAt)];
+                $pEndRaw = trim((string) ($encounter['period_end'] ?? ''));
+                if ($pEndRaw !== '') {
+                    $pEndIso = $this->normalizeIsoDateTime($pEndRaw);
+                    if ($pEndIso !== '') {
+                        $encounterRes['period']['end'] = $pEndIso;
+                    }
                 }
             }
             if ($practitionerRef !== '') {
@@ -809,7 +812,9 @@ class FhirR4Builder
                 if ($refHigh !== null && is_numeric($refHigh)) {
                     $rr['high'] = ['value' => (float) $refHigh, 'unit' => $unit ?: $ucum, 'system' => 'http://unitsofmeasure.org', 'code' => $ucum];
                 }
-                $obsResource['referenceRange'] = [$rr];
+                if (! empty($rr)) {
+                    $obsResource['referenceRange'] = [$rr];
+                }
             }
             // Interpretation (H/L/N)
             $interp = trim((string) ($obs['interpretation'] ?? ''));
@@ -1400,6 +1405,28 @@ class FhirR4Builder
         return (new \DateTime('now', new \DateTimeZone('Asia/Kolkata')))->format('Y-m-d\TH:i:sP');
     }
 
+    /**
+     * Normalize any datetime-like string into ISO 8601 with IST offset.
+     */
+    private function normalizeIsoDateTime(string $value, string $fallback = ''): string
+    {
+        $raw = trim($value);
+        if ($raw === '') {
+            return trim($fallback);
+        }
+
+        try {
+            $hasTimezone = preg_match('/([+-]\d{2}:\d{2}|Z)$/', $raw) === 1;
+            $dt = $hasTimezone && strpos($raw, 'T') !== false
+                ? new \DateTime($raw)
+                : new \DateTime($raw, new \DateTimeZone('Asia/Kolkata'));
+
+            return $dt->setTimezone(new \DateTimeZone('Asia/Kolkata'))->format('Y-m-d\TH:i:sP');
+        } catch (\Throwable $e) {
+            return trim($fallback);
+        }
+    }
+
     /**
      * @param array<string, mixed> $patient
      *
@@ -1435,8 +1462,9 @@ class FhirR4Builder
             'name'         => [$nameEntry],
         ];
 
-        if (! empty($patient['gender'])) {
-            $resource['gender'] = (string) $patient['gender'];
+        $gender = $this->normalizeAdministrativeGender($patient['gender'] ?? null);
+        if ($gender !== '') {
+            $resource['gender'] = $gender;
         }
 
         if (! empty($patient['birthDate'])) {
@@ -1471,6 +1499,25 @@ class FhirR4Builder
         return $resource;
     }
 
+    /**
+     * Convert legacy/local gender values to FHIR AdministrativeGender.
+     */
+    private function normalizeAdministrativeGender($value): string
+    {
+        $raw = strtolower(trim((string) $value));
+        if ($raw === '') {
+            return '';
+        }
+
+        return match ($raw) {
+            'm', 'male', '1' => 'male',
+            'f', 'female', '2' => 'female',
+            'o', 'other', '3', 'transgender', 'trans' => 'other',
+            'u', 'unknown', '0', 'na', 'n/a', 'not known' => 'unknown',
+            default => in_array($raw, ['male', 'female', 'other', 'unknown'], true) ? $raw : 'unknown',
+        };
+    }
+
     /**
      * Map common route-of-administration text to SNOMED CT codes.
      * Returns empty string when no mapping is found.